JP2009091300A - 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 cis-1,2,3,3,3-pentafluoropropene comprises introducing a raw material containing trans-1,2,3,3,3-pentafluoropropene into a reaction region filled with a catalyst comprising the carbon carrying a compound of a metal such as chromium or antimony in a gas phase to contact the trans-1,2,3,3,3-pentafluoropropene with the catalyst. <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 present inventors contact trans-1,2,3,3,3-pentafluoropropene represented by the following formula (1) with carbon carrying a metal compound in a gaseous state. As a result, it was found that isomerization into cis-1,2,3,3,3-pentafluoropropene represented by the following formula (2) was possible, and the present invention was achieved.

That is, the present invention is as follows.
[Claim 1] of cis-1,2,3,3,3-pentafluoropropene comprising contacting trans-1,2,3,3,3-pentafluoropropene and carbon carrying a metal compound. Production method.
[Claim 2] The metal compound supported on carbon is a compound of at least one metal selected from the group consisting of aluminum, chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony, or a mixture thereof. The method for producing cis-1,2,3,3,3-pentafluoropropene according to claim 1.
[3] The trans-1,2,3,3,3-pentafluoropropene is a mixture containing at least cis-1,2,3,3,3-pentafluoropropene. A process for producing cis-1,2,3,3,3-pentafluoropropene described in 1.
[Claim 4] The trans-1,2,3,3,3-pentafluoropropene in contact with carbon carrying a metal compound in the gas phase. A method for producing 1,2,3,3,3-pentafluoropropene.
[5] The process for producing cis-1,2,3,3,3-pentafluoropropene according to any one of [1] to [4], wherein the reaction temperature is -10 to 400 ° C.

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

  The method for producing cis-1,2,3,3,3-pentafluoropropene according to the present invention comprises contacting a trans-1,2,3,3,3-pentafluoropropene with a catalyst comprising carbon carrying a metal compound. Isomerization.

  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.

  When a supported catalyst in which a metal compound is supported on carbon is used as the catalyst, activated carbon is usually used as the support carbon. Activated carbon is a plant based on wood, sawdust, charcoal, coconut shell charcoal, palm kernel charcoal, raw ash, etc., coal based on peat, lignite, lignite, bituminous coal, anthracite, petroleum residue, There are petroleum-based or synthetic resin raw materials that use sulfuric acid sludge, oil carbon, and the like as raw materials.

  Since such activated carbon is commercially available, it can be selected from among them. For example, activated carbon manufactured from bituminous coal (for example, Calgon granular activated carbon CAL (manufactured by Toyo Calgon Co., Ltd.), coconut shell charcoal (for example, granular white birch G series (manufactured by Takeda Pharmaceutical Co., Ltd.)) and the like can be mentioned. However, of course, it is not limited to these types and manufacturers.

  In addition, these activated carbons are usually used in granular form such as crushed coal, granulated coal, granulated coal, spheroidal coal, etc., but the shape and size are not particularly limited, and based on the size of the reactor with ordinary knowledge Can be determined. In general, a sphere-shaped one having an average diameter of about 1 to 10 mm is selected because it is easy to handle.

  Examples of the metal of the metal compound to be supported include aluminum, chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony. Of these, aluminum, chromium, titanium, zirconium and antimony are preferred. These metals are used as oxides, fluorides, chlorides, fluorinated chlorides, oxyfluorides, oxychlorides, oxyfluorinated chlorides, etc., and two or more metal compounds may be supported together.

  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% by mass, preferably 1 to 50% by 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 to be supported include nitrates, chlorides, oxides, and the like of the corresponding metals that dissolve 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.

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

  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 reaction mixture by gas chromatography (unless otherwise specified, the detector is FID).

[Preparation Example 1] A 40% by mass CrCl ₃ aqueous solution of a commercially available reagent was diluted to prepare a 20% by mass aqueous solution. Diameter 4 to 6 mm, surface area 1200m2 / g, pore size 18 Å granular activated carbon (Takeda Chemical Industries, granular Shirasagi GX) 100 g was immersed in 20 wt% CrCl ₃ aqueous solution 156g previously prepared and allowed to stand overnight. Next, the activated carbon was taken out by filtration, kept at 100 ° C. in a hot air circulation dryer, and further dried overnight. The obtained chromium-supported activated carbon is filled into a cylindrical SUS316L reaction tube having a diameter of 2.5 cm and a length of 40 cm equipped with a heating device, and the temperature is raised to 300 ° C. while flowing nitrogen gas. At that time, the concentration of hydrogen fluoride was gradually increased with nitrogen gas, the reactor temperature was raised to 350 ° C., and the state was maintained for 1 hour to prepare a catalyst.

  [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 1. 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 was further raised to 300 ° C., and hydrogen fluoride was introduced in the same manner.

  The temperature of the reaction tube was changed to 170 ° C., the flow rate of nitrogen gas was reduced to 15 ml / min, and a cis-trans-OHFC-1225ye mixture (cis isomer 12.34%, trans isomer 86.8%) was previously prepared as a raw material organic substance. Vaporization was started and feeding to the reactor was started at a rate of 0.13 g / min (contact time 119 seconds). Since the reaction was stable 2 hours after the start of the reaction, the gas discharged 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 1-1).

  Thereafter, the temperature of the reaction tube and the reaction time (contact time) were changed as shown in Table 1, and after the reaction was stabilized, the gas flowing out from the reactor was blown into water to remove the acidic gas, Analyzed by gas chromatography. The results are shown in Table 1 (Examples 1-2 and 1-3).

  [Preparation Example 2] 100 g of granular activated carbon (Takeda Pharmaceutical, granular white GX) having a diameter of 4 to 6 mm, a surface area of 1200 m <2> / g, and a pore diameter of 18 angstrom was kept at 100 [deg.] C. in a hot air circulation drier and dried overnight. Prepared.

  [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 2. While flowing nitrogen gas at a flow rate of about 20 ml / min, the temperature of the reaction tube was raised to 280 ° C., and the flow rate of nitrogen gas was reduced to 15 ml / min. %, Trans isomer 86.8%) was vaporized in advance and started to be fed to the reactor at a rate of 0.15 g / min (contact time 74 seconds). Since the reaction was stable 2 hours after the start of the reaction, the gas discharged 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.

  [Preparation Example 3] 100 g of granular activated carbon (Takeda Pharmaceutical Co., Ltd., granular Hakuho GX) was dried under reduced pressure at 150 ° C. for 2 hours using a rotary evaporator. 100 g of antimony pentachloride was slowly introduced into the dried activated carbon at room temperature (25 ° C.) with stirring and supported.

  [Example 2] Antimony-supported activated carbon prepared in Preparation Example 3 was charged into a cylindrical reaction tube made of SUS316L having a diameter of 2.5 cm and a length of 40 cm equipped with a heating device, and 50 ml was charged. The temperature was raised to 80 ° C. while flowing nitrogen gas at a flow rate of about 10 ml / min, and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour.

  The introduction of hydrogen fluoride was stopped, and a mixture of cis and trans-OHFC-1225ye (cis isomer 12.34%, trans isomer 86.8%) was vaporized in advance as an organic raw material, and 0.05 g / min (contact time 162 seconds) Feeding to the reactor at a rate of Since the reaction was stable at 86 ° C. 1 hour after the start of the reaction, the gas discharged 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 (Example 2-1).

  Thereafter, the temperature of the reaction tube was changed as shown in Table 1, and after the reaction was stabilized, 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 (Examples 2-2 and 2-3).

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

Claims (5)

A process for producing cis-1,2,3,3,3-pentafluoropropene comprising contacting trans-1,2,3,3,3-pentafluoropropene with carbon carrying a metal compound. 2. The metal compound supported on carbon is a compound of at least one metal selected from the group consisting of aluminum, chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony, or a mixture thereof. A process for producing cis-1,2,3,3,3-pentafluoropropene. The cis-- according to claim 1, wherein the trans-1,2,3,3,3-pentafluoropropene is a mixture containing at least cis-1,2,3,3,3-pentafluoropropene. A method for producing 1,2,3,3,3-pentafluoropropene. The cis-1,2,3 according to any one of claims 1 to 3, which comprises contacting trans-1,2,3,3,3-pentafluoropropene with carbon carrying a metal compound in a gas phase. , 3,3-Pentafluoropropene production method. The process for producing cis-1,2,3,3,3-pentafluoropropene according to any one of claims 1 to 4, wherein the reaction temperature is -10 to 400 ° C.