JP3831987B2 - Process for producing 1,1,1,3,3-pentafluoropropane - Google Patents

Description

【００５５】
【表２】

【００５６】
【発明の効果】
本反応に用いる原料Ｒ２４０ｆは熱的、化学的に不安定な化合物であり、脱塩酸などの分解反応により１，３，３，３−テトラクロロプロペンなどの化合物に分解しやすく、さらにはタール化、オレフィンなどの分解生成物による触媒の還元により触媒の活性低下を引き起こしやすい。
【００５７】
本発明に従い、原料Ｒ２４０ｆとフッ化水素を触媒の非存在下に反応させて適度にフッ素化された中間体を得た後、この中間体を触媒の存在下フッ化水素によりさらにフッ素化することにより、触媒の耐久性を向上させ、触媒を失活させることなく長期に亙って容易に高収率でＲ２４５ｆａを製造できる。本発明は、工業的スケールで製造が困難であったＲ２４５ｆａを、簡便に、また触媒の失活を抑制することにより長期間高収率で製造しうるという効果を有する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improved process for producing 1,1,1,3,3-pentafluoropropane (hereinafter abbreviated as R245fa). R245fa is a hydrofluorocarbon (HFC) that does not destroy the ozone layer useful as a foaming agent or the like.
[0002]
[Prior art]
As a method for producing 245fa, (1) a method of hydrogenating CF ₃ CH═CF ₂ in the presence of a Pd catalyst (Izvest. Akad. Nauk SSSR, Otdel. Khim. Nauk. 1960, 1412), (2) CF ₃ CCl ₂ CClF ₂ how to hydrogen reduction in the presence of a Pd catalyst (U.S. Pat. No. 2,942,036), ₍₃₎ a method of the CF 3 CClHCClF ₂ to hydrogen reduction in the presence of a Pd catalyst (JP-a-6-256235 (4) CCl ₃ CH ₂ CCl ₃ is fluorinated with hydrogen fluoride to form CF ₃ CH ₂ CClF ₂ and then reduced with hydrogen in the presence of a hydrogenation catalyst (Japanese Patent Laid-Open No. 7-138194). _{JP), (5) CF y Cl} 3-y CH 2 CHF w Cl 2-w (y: 0~3 integer, w: a compound represented by the integer from 0 to 2) in the presence of a catalyst 50-175 Method of fluorination with hydrogen fluoride in the temperature range of ℃ ( O 96/01797), and (6) a method of fluorinating (JP-A-8-104655) are known from the hydrogen fluoride CCl ₃ CH ₂ CHCl ₂ with the presence of a catalyst under liquid phase.
[0003]
[Problems to be solved by the invention]
In the method (1), it is difficult to obtain raw materials industrially. In both methods (2) and (3), Pd is used as the reduction catalyst, but the reaction activity and heat resistance are insufficient, and it is not suitable as an industrial production method. In the method (4), it is difficult to selectively produce only CF ₃ CH ₂ CClF ₂ by fluorination, and it is difficult to finally increase the yield of R245fa. In the methods (5) and (6), the starting material CCl ₃ CH ₂ CHCl _{2 and the} like are chemically unstable and the yield reduction due to side reactions becomes remarkable, and the catalyst is easily deactivated.
[0004]
[Means for Solving the Problems]
The present invention is a method for producing R245fa that overcomes the disadvantages found in conventional methods, and 1,1,1,3,3-pentachloropropane (hereinafter abbreviated as R240f) is fluorinated in the absence of a fluorination catalyst. A partial fluorination reaction product obtained by fluorination with hydrogen is fluorinated with hydrogen fluoride in the presence of a fluorination catalyst containing a halide of one or more elements selected from antimony, niobium and tantalum. This is a manufacturing method of R245fa.
[0005]
It is known that R240f can be easily synthesized by radical addition reaction of vinyl chloride and carbon tetrachloride, which are general-purpose monomers (Takezo Asahara et al., Industrial Chemical Journal, 72, 1516 (1969), TAOnishchenko et al. .al., Izv.Akad.Nauk SSSR, Ser.Khim., 1972,1770, M.Kotora et.al., React.Kinet.Catal.Lett., 44,415 (1991), M.Kotora et.al., J. Mol. Catal., 77, 51 (1992)).
[0006]
In the absence of a fluorination catalyst, R240f is fluorinated with hydrogen fluoride to obtain a partially fluorinated reaction product (hereinafter abbreviated as a pre-stage reaction), and the resulting partially fluorinated reaction product is converted into a fluorination catalyst. The fluorination reaction (hereinafter abbreviated as a post-reaction) to obtain R245fa by fluorination with hydrogen fluoride in the presence of is preferably a liquid phase reaction under normal pressure or pressure.
[0007]
The partially fluorinated reactant obtained in the preceding reaction is preferably an average of 1 to 4, more preferably an average of 1 to 3 partially fluorinated propanes having fluorine atoms, and an average of 1 to 1 It means a mixture containing four, more preferably a partially fluorinated propene having fluorine atoms in an average ratio of 1 to 3 and the like.
[0008]
The partially fluorinated propane is a compound in which a chlorine atom in R240f is substituted with a fluorine atom, or a by-product chlorinated propene such as 1,3,3,3-tetrachloropropene which is a dehydrochloride of R240f. An addition compound in which a fluorine atom is added to the double bond, or a compound in which a chlorine atom in the addition compound is substituted with a fluorine atom.
[0009]
The partially fluorinated propene is a by-product chlorination such as dehydrochloride of partially fluorinated propane having a chlorine atom or 1,3,3,3-tetrachloropropene which is a dehydrochloride of R240f. It means a compound in which a chlorine atom in propene is substituted with a fluorine atom.
[0010]
As individual compounds in this partially fluorinated reaction product, non-fluorinated compounds such as R240f, 1,3,3,3-tetrachloropropene or five chlorine atoms such as R245fa are completely converted to fluorine atoms. Substituted compounds may be included.
[0011]
As the partial fluorination reaction product, 1,1,3,3-tetrachloro-1-fluoropropane (R241fa), 1,1,3-trichloro-1,3-difluoropropane (R242fb), 1,3,3 -Trichloro-1,1-difluoropropane (R242fa), 3,3-dichloro-1,1,1-trifluoropropane (R243fa), 1,3-dichloro-1,1,3-trifluoropropane (R243fb) 1,1-dichloro-1,3,3-trifluoropropane (R243fc), partially fluorinated propane such as 3-chloro-1,1,1,3-tetrafluoropropane (R244fa), 1-chloro-3 , 3,3-trifluoropropene (R1233zd), 1,3-dichloro-3,3-difluoropropene (R1232zd), 3,3- Partially fluorinated propenes such as chloro-1,3-difluoropropene (R1232ze), 1,3,3-trichloro-3-fluoropropene (R1231zd), 1,3,3,3-tetrafluoropropene (R1234ze) It is done.
[0012]
These partially fluorinated reactants are more stable than R240f, and are unlikely to by-produce decomposition products that cause a decrease in catalyst activity in the subsequent reaction.
[0013]
The reaction temperature of the first stage reaction is usually 50 ° C to 300 ° C, preferably 80 ° C to 250 ° C, particularly preferably 100 ° C to 200 ° C. It is preferable to carry out the reaction at a reaction temperature equal to or higher than the reaction temperature of the subsequent reaction.
[0014]
The reaction temperature of the latter reaction varies depending on the composition of the partially fluorinated reaction product obtained by the fluorination of the former reaction, but is usually 0 ° C to 200 ° C, preferably 30 ° C to 150 ° C. When the partially fluorinated reactant contains a large amount of partially fluorinated propene, it is preferable to carry out the reaction at a higher temperature.
[0015]
In the preceding reaction, the molar ratio of hydrogen fluoride to R240f is preferably in the range of R240f: hydrogen fluoride = 1: 1 to 1:30, considering the reaction vessel efficiency, loss due to the recovery of hydrogen fluoride, and the like. A range of 10 is more preferred. Unreacted hydrogen fluoride may be recycled after recovery and separation, and can also be used in the subsequent reaction together with the partially fluorinated reactant.
[0016]
The supply molar ratio of hydrogen fluoride to the partially fluorinated reactant obtained in the previous reaction is not particularly limited as long as it is at least the stoichiometric amount. Considering the reaction vessel efficiency, loss due to hydrogen fluoride recovery, and the like, the range of 1 to 10 moles relative to the stoichiometric amount is preferable, and the range of 1 to 5 moles is more preferable. The hydrogen fluoride supplied in the latter stage may be used in combination with the unreacted hydrogen fluoride in the former stage, or the unreacted hydrogen fluoride in the former stage may be used without newly supplying hydrogen fluoride in the latter stage. .
[0017]
In the pre-stage or post-stage reaction, hydrogen fluoride may be charged in advance before the reaction, or may be blown into the liquid phase during the reaction.
[0018]
The reaction pressure of the first stage reaction is usually 0 to 100 kg / cm ² · G, preferably 0 to 40 kg / cm ² · G, although it depends on the reaction temperature and the molar ratio of hydrogen fluoride to be added.
[0019]
The reaction pressure of the latter reaction is usually 0 to 40 kg / cm ² · G, but when the partially fluorinated propene contained in the partially fluorinated reaction product obtained in the former reaction is 5 kg / cm ² · G or more. High pressure is preferred. Moreover, when using a solvent, it changes also with the kind etc. of solvent.
[0020]
The partially fluorinated reactant obtained in the first stage reaction may be used in the second stage reaction after removing the hydrogen chloride by-produced by normal separation operations such as distillation purification, excess hydrogen fluoride, etc. It is preferable to use the obtained reaction mixture composed of hydrogen chloride, hydrogen fluoride, partially fluorinated reactant, etc. as it is for the subsequent reaction without undergoing a separation operation. When undergoing the separation operation, it is preferable to remove at least hydrogen chloride.
[0021]
The amount of the fluorination catalyst used in the subsequent reaction is not particularly limited. As the fluorination catalyst, a catalyst containing a halide of an element selected from Sb, Nb and Ta, or a catalyst containing such a catalyst as a main catalyst and another metal halide as a co-catalyst is preferable. The halogenated Sb is a pentavalent Sb halide, for example, a halogen represented by the general formula SbCl _x F _y (x and y are positive numbers satisfying x + y = 5, 0 ≦ x ≦ 5 and 0 ≦ y ≦ 5). Sb or the like is preferable.
[0022]
The metal halide catalyst acting as a promoter is selected from a metal halide selected from Cr, Fe, Ni, Cu, Zn, Ti, Zr, Hf, Sn, Pb and As, a trivalent Sb halide, and the like. One or more halides are preferred.
[0023]
Specifically, CrCl ₃ , FeCl ₃ , NiCl ₂ , CuCl ₂ , ZnCl ₂ , TiCl ₄ , TiF ₄ , ZrCl ₄ , ZrF ₄ , HfCl ₄ , HfF ₄ , SnCl ₄ , SnF ₄ , SnCl ₂ , PbCl ₄ , AsCl ₅ , one or more halides selected from SbCl ₃ and SbF ₃ are preferable, and in particular, one or more halides selected from SnCl ₄ , SnF ₄ , SnCl ₂ , TiCl ₄ , TiF ₄ , SbCl ₃ and SbF _3. Is preferred.
[0024]
When the fluorination catalyst contains halogenated Sb, the general formula SbCl _x F _y (x is a positive number from 0 to 1, y is obtained by always allowing an excess amount of hydrogen fluoride to coexist with the halogenated Sb. A positive number of 4 to 5, and a halogenated Sb represented by x + y = 5) is particularly preferable because early catalyst deactivation can be suppressed.
[0025]
Further, when a catalyst having a high chlorine content such as SbCl ₅ or SbCl ₂ F ₃ is used as the initial catalyst, the amount of fluorine in the catalyst (y in the above general formula) is obtained by reacting with excess hydrogen fluoride in advance. After the value) is set to 4 or more, the raw material supply is started and the reaction is performed.
[0026]
In the former stage and latter stage reactions, the reaction raw materials and products are usually used as the reaction solvent, but other reaction solvents may be used. In this case, the solvent dissolves the raw materials, and the solvent itself is more fluorine than the raw materials. There is no particular limitation as long as it is difficult to form. Examples of such a solvent include hydrofluorocarbons, perfluorocarbons such as perfluorooctane, and perfluoropolyethers.
[0027]
Examples of the partially fluorinated reactant distilled from the reactor together with the product R245fa include R241fa, R242fb, R242fa, R243fc, R243fa, R243fb, R243fc, R244fa, R1233zd, R1232ze, R123zze, R123zze, and R123zze.
[0028]
These partially fluorinated reactants are more stable in the presence of a fluorination catalyst than the raw material R240f, and are difficult to by-produce decomposition products that cause a decrease in catalytic activity. Therefore, after separation and purification with R245fa, Alternatively, it can be returned to the subsequent reaction system and used as a raw material for R245fa.
[0029]
The pre-stage and post-stage reactions can be performed as a batch reaction or a continuous reaction. As the continuous reactor, either a complete mixing tank type in which raw materials and hydrogen fluoride can be sufficiently mixed, or a piston flow type using a static mixer or the like may be used.
[0030]
As the material of the reactor, a normal material such as a stainless steel material such as SUS304 or SUS316, or a nickel alloy such as Hastelloy (trade name), Inconel (trade name), or Monel (trade name) can be used. The stainless steel material does not contain aluminum, and the nickel content of the nickel material is known to be about 4% by weight at maximum.
[0031]
The nickel-based alloy is less corrosive than a stainless steel material, but a corrosion-resistant metal material made of aluminum or a corrosion-resistant metal material containing 10 wt% or more of aluminum is preferable because the corrosion resistance is further reduced.
[0032]
A desirable ratio of aluminum in the corrosion-resistant metal material is 20% by weight or more, and particularly 30% by weight or more. The upper limit of the ratio of aluminum is a ratio in which the corrosion-resistant metal material is substantially made of aluminum. The fact that the corrosion-resistant metal material is substantially made of aluminum means that a trace amount of metal impurities other than aluminum mixed in production may be contained.
[0033]
By using the reactor having the inner surface made of the corrosion-resistant metal material, the deterioration of the apparatus due to the corrosion is reduced, and the reaction can be continued with good results for a long period without impairing the catalytic activity.
[0034]
The corrosion-resistant metal material is used as it is as a material for the reactor, or one or more of the corrosion-resistant metal materials is used as a surface material (hereinafter referred to as a clad material), and one or more other materials are used as a base material for the corrosion-resistant metal material. It can also be used as a composite material (hereinafter referred to as a core material).
[0035]
The core material is not particularly limited as long as it satisfies various properties required for a reactor other than corrosion resistance, such as strength, weldability, thermal conductivity, etc., usually carbon steel, stainless steel, nickel-based alloy, Aluminum or the like is used. In order to improve the adhesion between the core material and the corrosion-resistant metal material, the core material may have two or more layers. As a method for producing the composite material, there is a method in which a corrosion-resistant metal material is composited by a method such as plating, thermal spraying, and explosion deposition on the core material.
[0036]
In order to protect the core material from the corrosive environment, the corrosion-resistant metal material used as the clad material preferably forms a dense layer without cracks, and its thickness depends on the manufacturing method and the selected corrosion-resistant metal material. Although not limited, it is appropriate to have a certain thickness considering the durability and mechanical strength of the material, that is, preferably 10 μm to 30 mm, more preferably 30 μm to 10 mm, and particularly preferably 100 μm to 10 mm.
[0037]
In general, the surface of a corrosion-resistant metal material is covered with a metal oxide, and a passive state is formed. In this fluorination reaction, it is desirable that at least a part of the surface of the corrosion-resistant metal material is covered with a protective film containing a metal fluoride. In particular, it is more desirable in a corrosion-resistant metal material containing a metal component having a relatively low standard oxidation potential such as aluminum and magnesium. By being covered with a protective film containing a metal fluoride, a more stable passivation is formed, and excellent corrosion resistance is exhibited even in an environment of a super strong acid as in the present fluorination reaction system.
[0038]
Although it is desirable to form the protective film containing a metal fluoride before the reaction, it is also possible to form a protective film during the reaction. In order to form a protective film containing at least a metal fluoride before the reaction, a reactor whose inner surface is covered with a corrosion-resistant metal material may be treated with a suitable fluorinating agent.
[0039]
The fluorinating agent is not particularly limited, and for example, fluorine gas, hydrogen fluoride, antimony pentafluoride and the like are used. The treatment temperature depends on the corrosion-resistant metal material used, but in the case of fluorine gas, it is preferably 0 ° C. to 300 ° C., particularly preferably room temperature to 200 ° C., and the fluorine gas is usually an inert gas such as nitrogen, and the fluorine gas concentration Is adjusted to 20 to 100% by volume.
[0040]
In the case of hydrogen fluoride, it is preferably 0 ° C. to 300 ° C., particularly preferably room temperature to 300 ° C., and anhydrous hydrogen fluoride is used in liquid or gaseous form. In the case of antimony pentafluoride, it is preferably 0 ° C to 200 ° C, particularly preferably room temperature to 120 ° C. These fluorinating agents may be used alone, or two or more of them may be used simultaneously or stepwise.
[0041]
In a corrosion-resistant metal material containing aluminum as a corrosion-resistant component, the corrosion-resistant component in the present fluorination reaction environment is essentially a fluoride containing aluminum existing on the outermost surface of the corrosion-resistant metal material. The amount of the aluminum component necessary for forming the protective film of fluoride may be small, and even if the content is about 10% by weight as a metal component in the corrosion-resistant metal material, the effect can be sufficiently exerted.
[0042]
The corrosion-resistant metal material in the present invention may be industrial pure aluminum, may be a material containing 10% by weight or more of aluminum, and one or more selected from iron, copper, manganese, magnesium, cobalt and chromium as subcomponents, For example, Fe-Cr-Al alloy, Cu-Al alloy, etc. are mentioned. Aluminum containing the subcomponents has improved properties such as strength as compared with industrial pure aluminum, and can be used not only as a cladding material for a reactor but also as a core material.
[0043]
【Example】
Example 1 (Example)
A 2-liter Hastelloy C autoclave was charged with 500 g of R240f and 460 g of HF. The autoclave is heated to 120 ° C., HCl generated as a by-product in the reaction is purged from a cooling tube kept at 110 ° C., and the reaction is carried out for 5 hours while maintaining the reaction pressure at 22 kg / cm ² · G or less. R241fa and R1233zd A reaction mixture containing was obtained. The conversion rate of R240f was 99 mol%, the selectivity of R241fa was 45 mol%, and the selectivity of R1233zd was 55 mol%.
[0044]
Next, 360 g of SbF ₅ and 330 g of HF were charged into a 1 liter autoclave lined with polytetrafluoroethylene. After raising the temperature of the autoclave to 80 ° C., the reaction mixture containing HF at an average feed rate of 20 g / hr (1.0 mol / hr) and R241fa and R1233zd was added at an average feed rate of 50 g / hr (0.31 mol). / Hr) to start the reaction.
[0045]
The reaction pressure was controlled to 7.5 to 8.5 kg / cm ² · G, and the product was continuously distilled together with HCl and unreacted HF produced as by-products in the reaction from a cooling tube kept at 70 ° C. Table 1 shows organic components in the distillate gas after 24 hours.
[0046]
Example 2 (Example)
The reaction was conducted in the same manner as in Example 1 except that 360 g of SbF ₅ and 40 g of SnCl ₄ were used as the catalyst. Table 2 shows the organic components in the distillate gas after 24 hours.
[0047]
Example 3 (Example)
The reaction was conducted in the same manner as in Example 1 except that 360 g of SbF ₅ and 40 g of SbF ₃ were used as the catalyst. Table 2 shows the organic components in the distillate gas after 24 hours.
[0048]
Example 4 (Example)
The reaction was performed in the same manner as in Example 1 except that 360 g of SbF ₅ and 40 g of TiCl ₄ were used as catalysts. Table 2 shows the organic components in the distillate gas after 24 hours.
[0049]
Example 5 (Example)
The reaction was carried out in the same manner as in Example 1 except that 360 g of NbCl ₅ was used as the catalyst. Table 1 shows organic components in the distillate gas after 24 hours.
[0050]
Example 6 (Example)
The reaction was carried out in the same manner as in Example 1 except that 360 g of TaCl ₅ was used as the catalyst. Table 1 shows organic components in the distillate gas after 24 hours.
[0051]
Example 7 (Example)
Table 1 shows the organic components in the distillate gas after 180 hours instead of the distillate gas after 24 hours in the reaction of Example 1.
[0052]
Example 8 (comparative example)
In a 1 liter autoclave lined with polytetrafluoroethylene, 360 g of SbF ₅ and 330 g of HF were charged. After raising the temperature of the autoclave to 80 ° C., HF was fed at an average feed rate of 20 g / hr (1.0 mol / hr), and R240f was fed at an average feed rate of 40 g / hr (0.18 mol / hr). Started.
[0053]
The reaction pressure was controlled to 7.5 to 8.5 kg / cm ² · G, and the product was continuously distilled together with HCl and unreacted HF produced as by-products in the reaction from a cooling tube kept at 70 ° C. Table 1 shows the organic components in the distillate gas after 180 hours.
[0054]
[Table 1]

[0055]
[Table 2]

[0056]
【The invention's effect】
The raw material R240f used in this reaction is a thermally and chemically unstable compound, and is easily decomposed into a compound such as 1,3,3,3-tetrachloropropene by a decomposition reaction such as dehydrochlorination. Reduction of the catalyst by a decomposition product such as olefin tends to cause a decrease in the activity of the catalyst.
[0057]
According to the present invention, a raw material R240f and hydrogen fluoride are reacted in the absence of a catalyst to obtain a moderately fluorinated intermediate, and then this intermediate is further fluorinated with hydrogen fluoride in the presence of a catalyst. Thus, the durability of the catalyst can be improved, and R245fa can be easily produced in a high yield over a long period of time without deactivating the catalyst. INDUSTRIAL APPLICABILITY The present invention has an effect that R245fa, which has been difficult to produce on an industrial scale, can be produced in a high yield for a long period of time simply and by suppressing the deactivation of the catalyst.

Claims (4)

One or more elements selected from antimony, niobium and tantalum as a partially fluorinated reactant obtained by fluorinating 1,1,1,3,3-pentachloropropane with hydrogen fluoride in the absence of a fluorination catalyst A process for producing 1,1,1,3,3-pentafluoropropane, characterized by fluorination with hydrogen fluoride in the presence of a fluorination catalyst containing a halide of   The process according to claim 1, wherein the reaction temperature in the fluorination with hydrogen fluoride is 50 ° C to 300 ° C in the absence of the fluorination catalyst.   In the absence of a fluorination catalyst, the molar ratio of hydrogen fluoride to 1,1,1,3,3-pentachloropropane in fluorination with hydrogen fluoride is 1,1,1,3,3-pentachloropropane: The process according to claim 1 or 2, wherein hydrogen fluoride is in the range of 1: 1 to 1:30.   The process according to claim 1, 2 or 3, wherein the reaction temperature in fluorination with hydrogen fluoride is 0 to 200 ° C in the presence of a fluorination catalyst.