JP5601471B2 - Method for producing chlorine-containing fluoropropene - Google Patents

Description

  The present invention relates to a method for producing a chlorine-containing fluoropropene.

A chlorine-containing fluoropropene represented by the general formula: CFX ₂ CCl = CH ₂ (X is F or Cl, and may be the same or different) is a compound useful as a raw material or an intermediate for producing various fluorocarbons. Furthermore, it is also useful as a monomer component in various polymers and various functional materials. In particular, 2,3-dichloro-3,3-difluoropropene (HCFC-1232xf) represented by CF ₂ ClCCl═CH ₂ is a promising compound as a cleaning agent, a dry cleaning solvent, and a resist removal agent.

Among the compounds represented by the above general formula, 2,3,3-trichloro-3-fluoropropane (HCFC-1231xf, bp. 98.5-99 ° C.) represented by CFCl ₂ CCl═CH ₂ and CF ₂ The production method of 2,3-dichloro-3,3-difluoropropene (HCFC-1232xf, bp. 57-58 ° C) represented by ClCCl = CH ₂ is 1,1,2,3-tetrachloro-1 A method is known in which dehydrochlorination is performed by reacting 1-fluoropropane (HCFC-241db) or 1,2,3-trichloro-1,1-difluoropropane (HCFC-242dc) with an equivalent amount of KOH, respectively. (See Patent Document 1, Non-Patent Document 2, Patent Document 1, etc.). However, in this method, a large amount of waste is problematic, and the yield must be improved.

Also, 2-chloro-3,3,3-trifluoropropene represented by CF ₃ CCl = CH ₂ As a method for producing (HCFC-1233xf, bp. 14-15 ℃) is 1, 2-dichloro -3 , 3,3-trifluoropropane (HCFC-243db, bp. 76 ° C.) is known to have a method of removing HCl by reacting with an equivalent amount of KOH (Non-patent Documents 2 and 3). However, this method is not an economically suitable method because a large amount of waste is problematic and a long reaction time is required.

  In addition, when a halogenated hydrocarbon is reacted with hydrogen fluoride (HF) in the presence of a fluorination catalyst in the gas phase, it is known that a deHCl reaction proceeds depending on the reaction conditions to obtain HCFC-1233xf. (Patent Document 2, Patent Document 3). However, this method has problems of cost increase and catalyst deterioration due to the use of a catalyst, and further, there are many problems in utilization on an industrial scale such as the necessity of HF.

As described above, at present, a method capable of producing a chlorine-containing fluoropropene represented by the general formula: CFX ₂ CCl = CH ₂ in a high yield by a simple method so as to suit the economy has been established. Not in.

US 2787646 WO 2008/054781 A1 WO 2009/125199 A2 GB 772484

Inst. Heteroorg. Compds. 1960, pp447-51 Journal of the Chemical Society, 1953, pp3371-8 Journal of the Chemical Society, 1951, pp2495-504 Journal of the American Chemical Society, 1947, 69, pp944-7

The present invention has been made in view of the above-described state of the art, and the main object of the present invention is to provide a general formula: CFX efficiently by a simple and economically advantageous method suitable for implementation on an industrial scale. It is to provide a method capable of producing a chlorine-containing fluoropropene represented by ₂ CCl═CH ₂ (X is F or Cl, and may be the same or different).

The present inventor has intensively studied to achieve the above-described object. As a result, chlorine-containing fluoropropane represented by the general formula: CFX ₂ CHClCH ₂ Cl (X is F or Cl, which may be the same or different) is used as a raw material, and in a gas phase state without using a catalyst. Surprisingly, according to the method of sufficiently heating in a predetermined temperature range, the side reaction is suppressed by a one-step reaction operation, and the target CFX ₂ CCl = CH ₂ (X is the same as above) The chlorine-containing fluoropropene represented by the above can be produced with high selectivity, eliminating the drawbacks of the conventional method for producing a chlorine-containing fluoropropene, and efficiently producing the chlorine-containing fluoropropene on an industrial scale. The present invention has been completed here.

That is, the present invention provides a method for producing a chlorine-containing fluoropropene represented by the following general formula: CFX ₂ CCl═CH ₂ (X is F or Cl and may be the same or different). .
1. In the absence of a catalyst, chlorine-containing fluoropropane represented by the general formula: CFX ₂ CHClCH ₂ Cl (X is F or Cl, which may be the same or different) is heated in the gas phase to dechlorinate. A method for producing a chlorine-containing fluoropropene represented by the general formula: CFX ₂ CCl═CH ₂ (X is the same as above) characterized by causing a hydrogen reaction.
2. Item 2. The method for producing a chlorine-containing fluoropropene according to Item 1, wherein the heating temperature is 350 to 550 ° C.
3. Item 3. The method for producing a chlorine-containing fluoropropene according to Item 1 or 2, wherein an inert gas is supplied simultaneously with the chlorine-containing fluoropropane to perform a dehydrochlorination reaction.
4). Item 4. The method for producing a chlorine-containing fluoropropene according to Item 3, wherein 0.5 to 50 mol of an inert gas is supplied to 1 mol of the chlorine-containing fluoropropane.
5. After producing a chlorine-containing fluoropropene by the method according to any one of Items 1 to 4, the chlorine-containing fluoropropene comprising a step of returning the unreacted chlorine-containing fluoropropane contained in the reaction product to the reactor and reusing it. Manufacturing method.

  Hereinafter, the manufacturing method of the chlorine containing fluoropropene of this invention is demonstrated concretely.

(1) Raw Material Compound In the present invention, chlorine-containing fluoropropane represented by the general formula: CFX ₂ CHClCH ₂ Cl (X is F or Cl and may be the same or different) is used as the raw material compound. The compound represented by the above general formula is a known compound. As a specific example, 1,1,2,3-tetrachloro-1-fluoropropane (HCFC-241db, bp represented by the chemical formula: CFCl ₂ CHClCH ₂ Cl 157 ° C), chemical formula: CF ₂ ClCHClCH ₂ Cl, 1,2,3-trichloro-1,1-difluoropropane (HCFC-242dc, bp. 113-114 ° C), chemical formula: CF ₃ CHClCH ₂ Cl 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db, bp. 76 ° C.) and the like. Among these compounds, 1,1,2,3-tetrachloro-1-fluoropropane (HCFC-241db, bp. 157 ° C) and 1,2,3-trichloro-1,1-difluoropropane (HCFC) -242dc, bp. 113-114 ° C) can be easily obtained by, for example, a method of fluorinating 1,1,1,2,3-tetrachloropropane (HCC-240db) (see Non-Patent Document 1). ).

As a method for producing other HCFC-242dc, formula: CF ₂ ClCH = CH ₂ the compound represented by (HCFC-1242zf) or Formula: From the compound represented by _{CF 2 ClCHClCH 3 (HCFC-252dc} ), chlorine A method of chlorinating using benzene is known (see Patent Document 4, Non-Patent Document 4, etc.). As a method for producing 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db, bp. 76 ° C.), as shown in Patent Document 3, the chemical formula: CF ₃ CH═CH ₂ A method of chlorinating with chlorine using a compound represented by (HFC-1243zf) as a raw material is known.

By using a chlorine-containing fluoropropane represented by these general formulas: CFX ₂ CHClCH ₂ Cl (X is F or Cl and may be the same or different) as a raw material, the reaction is carried out according to the conditions described later. In the step reaction process, a dehydrochlorination reaction is allowed to proceed to produce a chlorine-containing fluoropropene represented by the target general formula: CFX ₂ CCl═CH ₂ (X is the same as above) with high selectivity.

(2) Reaction method The production method of the present invention is a method in which the above-described raw material compound is heated in a gas phase to cause a dehydrochlorination reaction.

In the method of the present invention, it is particularly important to heat the raw material compound in the absence of a catalyst when performing the dehydrochlorination reaction. Under such conditions, the raw material compound is heated and reacted, and the target general formula: CFX ₂ CCl = CH ₂ (X is the same as above) is obtained with a high selectivity by a one-step reaction process. The represented chlorine-containing fluoropropene can be obtained.

  In the method of the present invention, the reaction temperature is suitably about 300 to 650 ° C., more preferably about 350 to 550 ° C., and particularly preferably about 360 to 480 ° C. as the temperature in the reactor. By heating in such a temperature range, the target chlorine-containing fluoropropene can be obtained with high selectivity. When the heating temperature is higher than this range, by-products increase and the selectivity of the target chlorine-containing fluoropropene decreases. On the other hand, when the heating temperature is lower, the conversion rate of the raw material compound decreases. .

  In the present invention, it is particularly important to advance the dehydrochlorination reaction by sufficiently heating the raw material compound in the above temperature range. For this purpose, for example, by using a reaction tube having a sufficient length and heating the raw material compound by increasing the contact time; by increasing the heat transfer area of the raw material using a reaction tube having a small inner diameter, Method for improving heat transfer efficiency; filling the reaction tube with a material that has good thermal conductivity, no catalytic activity for the reaction of the present invention, and is stable with respect to the generated hydrogen chloride (HCl), and temperature distribution in the reaction tube It is preferable to adopt a method of making the reaction uniform and conducting the reaction.

  In this case, for the contact time, for example, the ratio between the volume V (cc) of the reaction space in the gas phase and the total flow rate Fo (flow rate at 0 ° C., 0.1 MPa: cc / sec) of the raw material gas flowing into the reaction system : The contact time represented by V / Fo is preferably in the range of about 5 to 100 sec, more preferably in the range of about 20 to 60 sec. Note that the total flow rate of the raw material gas described above is a total flow rate in which an inert gas is added when an inert gas described later is used in addition to the chlorine-containing fluoropropane used as a raw material.

  In the method of improving heat transfer efficiency using a reaction tube having a small inner diameter, for example, the relationship between the flow rate of the raw material and the inner diameter of the reaction tube is preferably such that the linear velocity is large and the heat transfer area is large. .

  In the method of filling materials having no catalytic activity, for example, hastelloy pieces, nickel beads or the like may be used as materials satisfying the above conditions, and these materials may be filled into the reaction tube. The shape of the material to be filled is not particularly limited, and may be any shape that can uniformly fill the reaction tube such as powder or pellets according to the shape of the reaction tube.

  By employing the heating method described above in the absence of a catalyst, it is possible to obtain the target chlorine-containing fluoropropene with particularly good selectivity.

  In the method of the present invention, the raw material compound may be present in a gaseous state in the reaction temperature region described above, and the raw material compound may be in a liquid state when the raw material compound is supplied. For example, the reaction can be carried out in the gas phase by vaporizing the raw material compound (vaporization region) using a vaporizer and then passing it through the preheating region. Alternatively, the raw material compound may be supplied to the reaction apparatus in a liquid state, and vaporized when the reaction region is reached to react. The method for vaporizing the raw material compound in the reaction region is not particularly limited.For example, it has good thermal conductivity such as the above-mentioned Hastelloy pieces and nickel beads, has no catalytic activity, and produces hydrogen chloride (HCl). Fill the reaction tube with a stable material, make the temperature distribution in the reaction tube uniform and heat it above the vaporization temperature of the raw material compound, supply the raw material compound in a liquid state here, vaporize the raw material compound, and vapor phase state It is good.

  The raw material compound may be supplied to the reactor as it is, but in particular, by supplying it to the reaction temperature region together with an inert gas, the side reaction is suppressed and the desired chlorine-containing fluoropropene is obtained with high selectivity. be able to. As the inert gas, for example, nitrogen, helium, argon or the like can be used. The supply amount of the inert gas is usually preferably in the range of about 0.5 to 50 mol, more preferably in the range of about 5 to 30 mol, relative to 1 mol of the raw material compound. By making the usage-amount of an inert gas into such a range, the selectivity of a chlorine containing fluoropropene can be maintained in a favorable range.

  The form of the reactor used in the method of the present invention is not particularly limited. For example, an empty reactor or a reactor filled with a metal or a medium can be used. As described above, the metal or medium to be filled is porous in various shapes, as long as it uses a material that has good thermal conductivity, does not have catalytic activity for the reaction, and is stable with respect to the generated hydrogen chloride (HCl). Materials and non-porous materials can be used. Using such a reactor, for example, the inside of the reactor may be heated to a predetermined temperature by heating from the outside with an electric furnace or the like. In addition, a multi-tubular reactor in which heat transfer, heat removal, and temperature distribution in the reactor are made uniform using a heat medium can also be used. As the reactor, it is preferable to use a reactor made of a material resistant to the corrosive action of hydrogen chloride, such as Inconel, HASTALLOY, Monel, and INCOLLOY.

  The pressure during the reaction is not particularly limited as long as the raw material compound can exist in a gas phase state, and may be any of normal pressure, pressurized pressure, and reduced pressure. That is, the production method of the present invention can be carried out under reduced pressure or atmospheric pressure (0.1 MPa), and can also be carried out under a pressure that does not cause the raw material to be in a liquid state.

According to the reaction conditions described above, a reaction product containing a chlorine-containing fluoropropene represented by the target general formula: CFX ₂ CCl═CH ₂ (X is the same as above) can be obtained at the reactor outlet. . The chlorine-containing fluoropropene can be purified and recovered by distillation or the like, and can be used as it is for the intended purpose or can be converted into other compounds.

  In the method of the present invention, since the selectivity of the target chlorine-containing fluoropropene is high, by returning the unreacted raw material to the reactor again for recycling, even if the raw material conversion rate is low, high productivity Can be maintained.

According to the method of the present invention, a chlorine-containing fluoropropane represented by the chemical formula CFX ₂ CHClCH ₂ Cl (X is F or Cl, which may be the same or different) is used as a raw material, and high selection is achieved by a one-step reaction operation. A chlorine-containing fluoropropene represented by the general formula: CFX ₂ CCl═CH ₂ (X is the same as above) can be produced.

  Further, the production method of the present invention can be carried out under mild conditions such as normal pressure and reduced pressure, and is a production method utilizing a gas phase reaction suitable for continuous production.

  Furthermore, according to the method of the present invention, the desired chlorine-containing fluoropropene can be obtained with high selectivity after eliminating all the disadvantages of the conventional production method using a catalyst.

  Therefore, the method of the present invention can be said to be an industrially advantageous method as a method for producing chlorine-containing fluoropropene.

The schematic of the reactor used in Examples 1-3.

  Hereinafter, the present invention will be described in more detail by describing examples of the present invention.

Example 1
Hereinafter, a specific example of a production method using 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) as a raw material will be shown.

A schematic diagram of the reactor used in this example is shown in FIG. In this reactor, a reactor made of tubular Inconel 600 with an outer diameter of 1/2 inch (wall thickness: 1.24 mm) and a length of 199 cm (reaction tube, internal volume: 163.2 cm ³ ) is assembled in a muffle furnace, and the reaction tube inlet side A line for supplying 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) and inert gas was connected to the connection part. A vaporizer was installed in the supply line of HCFC-243db, and HCFC-243db supplied in liquid state was vaporized at 140 ° C. Vaporized HCFC-243db is preheated at 200 ° C until it is supplied to the reactor. When supplying inert gas, the inert gas supply line is also preheated at 200 ° C and mixed with HCFC-243db. To the reactor. Both the inlet side and the outlet side of the reaction tube connecting part were connected by a pipe having an outer diameter of 1/8 inch, and the pipe volume in the muffle furnace was also regarded as a reaction space. The reaction space volume in the muffle furnace in this case was 164.0 cm ³ . All the pipes and joints other than the reaction tube were made of Hastelloy material.

Inside the muffle furnace, the space temperature in the furnace is measured at two points, this average temperature is taken as the furnace temperature, and the temperature of the outer wall of the reaction tube is measured at eight points at regular intervals from the inlet side to the outlet side. The temperature was taken as the reaction temperature. The reaction tube is maintained at atmospheric pressure (0.1 MPa), the reaction temperature is maintained at 400 ° C., and nitrogen (N ₂ ) is continuously supplied to the reactor at a flow rate of 200 cc / min (0 ° C., flow rate at 0.1 MPa). Feeded and maintained for 10 hours.

Thereafter, while maintaining the reaction temperature at 400 ° C. and supplying nitrogen (N ₂ ) at a flow rate of 200 cc / min (flow rate at 0 ° C. and 0.1 MPa), 1,2-dichloro-3,3,3 -Trifluoropropane (HCFC-243db, purity 99.8%) was continuously supplied at a rate of 20.0 cc / min (flow rate at 0 ° C., 0.1 MPa) to initiate the reaction. At this time, the furnace temperature was set so that the reaction temperature could be maintained at 400 ° C. The molar ratio (N ₂ / HCFC-243db) of nitrogen (N ₂ ) to 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) is 10, and the contact time (V / F ₀ ) From the reaction space volume (V) in the muffle furnace and the total flow rate of the reactant (F ₀ ), V / F ₀ = 44.7 sec.

  The effluent from the reactor 3 hours after the start of the reaction was analyzed using a gas chromatograph. Among the reaction products, the recovered amounts of high-boiling products having a boiling point of 50 ° C. or higher and the raw material HCFC-243db were quantified by the method described below. That is, HCFC-225 (225ca: 225cb = 57: 43) in which a predetermined amount of perchlorethylene was dissolved as an internal standard substance and ice water were mixed and separated, and the reactor outlet component was kept for a certain period of time. The organic matter was extracted with the HCFC-225 layer, and hydrogen chloride was dissolved in ice water.

  The extract was heated to 20 ° C., and the HCFC-225 layer was analyzed by gas chromatography (FID). A DB-1 (60m) capillary column is used as the column. From the detection area ratio of perchlorethylene, which is the internal standard substance, to HCFC-243db and other compounds, the coefficients in the gas chromatograph are taken into consideration, respectively. The amount of -243db was converted to a molar ratio, the raw material conversion was calculated from the recovered amount of HCFC-243db, and other product amounts were also calculated.

On the other hand, low boiling point substances having a boiling point of 50 ° C. or less were quantified by the method described below. That is, two washing towers containing water were connected and connected at the outlet of the reactor, immersed in a water bath and preheated to 60 ° C., then the reactor effluent was poured and bubbled to wash the acid content. Thereafter, the dehydrated gas components were collected through a CaCl ₂ tube and analyzed by gas chromatography (FID). At this time, a predetermined amount of difluoromethane (HFC-32) was caused to accompany the washing tower from the outlet side of the reactor as an internal standard substance. As the column, a gsgaspro (60m) capillary column was used, and the amount of each product produced, taking into account the coefficient in the gas chromatograph from the detection area ratio between the internal standard substance HFC-32 and each product. Was converted to a molar ratio. Table 1 shows the results of quantification of reactor outlet components using the above method.

The products in this example are as follows.
CF ₃ CCl = CH ₂ (HCFC-1233xf)
CF ₃ CH = CH ₂ (HFC-1243zf)
CF ₃ CH = CHCl (HCFC-1233zd) (The total of E and Z forms is listed in Table 1)
CH ₂ ClCCl = CF ₂ (HCFC-1232xc)
Example 2
The reaction was carried out under the same conditions as in Example 1 except that the supply amount of nitrogen (N ₂ ) was changed to 400 cc / min (flow rate at 0 ° C. and 0.1 MPa) and the reaction temperature was changed to 450 ° C. The molar ratio of nitrogen (N ₂ ) to 1,2-dichloro-3,3,3-trifluoropropane (N ₂ / HCFC-243db) was 20. The contact time (V / F ₀ ) was V / F ₀ = 23.4 sec from the reaction space volume (V) in the muffle furnace and the total flow rate of the reactant (F ₀ ). Table 1 shows the analysis results at 3 hours from the start of the reaction.

Example 3
The supply rate of nitrogen (N ₂ ) is 168 cc / min (flow rate at 0 ° C, 0.1 MPa) and 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db, purity 99.8%) The reaction was performed under the same conditions as in Example 1 except that the supply rate was changed to 28.0 cc / min (flow rate at 0 ° C., 0.1 MPa) and the reaction temperature was changed to 380 ° C. The molar ratio of nitrogen (N ₂ ) to 1,2-dichloro-3,3,3-trifluoropropane (N ₂ / HCFC-243db) was 6. The contact time (V / F ₀ ) was V / F ₀ = 50.2 sec from the reaction space volume (V) in the muffle furnace and the total flow rate of the reactant (F ₀ ). Table 1 shows the analysis results at 3 hours from the start of the reaction.

Claims (5)

In the absence of a catalyst, chlorine-containing fluoropropane represented by the general formula: CFX ₂ CHClCH ₂ Cl (X is F or Cl, which may be the same or different) is degassed at 350 to 550 ° C. in the gas phase. A method for producing a chlorine-containing fluoropropene represented by the general formula: CFX ₂ CCl═CH ₂ (X is the same as above) characterized by causing a hydrogen chloride reaction. The method for producing a chlorine-containing fluoropropene according to claim 1, wherein a dehydrochlorination reaction is caused at 360 to 480 ° C. The method for producing a chlorine-containing fluoropropene according to claim 1 or 2, wherein a dehydrochlorination reaction is performed by supplying an inert gas simultaneously with the chlorine-containing fluoropropane. The method for producing a chlorine-containing fluoropropene according to claim 3, wherein 0.5 to 50 mol of an inert gas is supplied to 1 mol of the chlorine-containing fluoropropane. A chlorine-containing fluoropropene comprising a step of producing a chlorine-containing fluoropropene by the method according to any one of claims 1 to 4 and then returning the unreacted chlorine-containing fluoropropane contained in the reaction product to the reactor for reuse. Manufacturing method.

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