WO2010001768A1

WO2010001768A1 - Process for producing fluorine-containing propene compounds

Info

Publication number: WO2010001768A1
Application number: PCT/JP2009/061432
Authority: WO
Inventors: Yuzo Komatsu; Akinari Sugiyama; Takashi Shibanuma
Original assignee: Daikin Industries, Ltd.
Priority date: 2008-07-01
Filing date: 2009-06-17
Publication date: 2010-01-07

Abstract

The present invention provides a process for producing a fluorine-containing propene compound represented by the formula CF₃CF=CYZ wherein Y and Z are the same and different and each represent a hydrogen atom or a halogen atom, the process comprising reacting a compound represented by the formula CF₂=CF₂ with a halogen-containing compound represented by the formula CHXYZ wherein X is chlorine, bromine, or iodine, and Y and Z are as defined above in the presence of at least one component selected from the group consisting of metal halides and metal oxides. The process of the present invention is a novel method for producing a fluorine-containing propene compound, such as CF₃=CH₂, with high selectivity in a comparatively simple manner.

Description

DESCRIPTION

Title of Invention: PROCESS FOR PRODUCING FLUORINE-CONTAINING PROPENE COMPOUNDS

Technical Field

The present invention relates to a process for producing a fluorine-containing propene compound.

Background Art

The fluorine-containing propene compound represented by the formula CF₃CF=CH₂ has low toxicity and a low global warming potential. Therefore, this compound is an excellent candidate as an alternative solvent. Accordingly, there has been desired a method of producing CF₃CF=CH₂ with high selectivity by a single- step reaction under industrially advantageous conditions using inexpensive materials.

Patent Literature 1 (PTL 1) listed below describes a process for producing CF₃CF=CH2 by reacting CF2=CF₂ and CH₃Cl in a gas phase at 850°C without using a catalyst. However, the yield of CF₃CF=CH₂ obtained by this process is about 5%, and is therefore not at a satisfactory level.

Regarding the CF₂=CF₂ used in the process of Patent Literature 1, Non-Patent Literature 1 (NPL 1) listed below describes producing various Ci-s fluorocarbons from CF₂=CF₂ at high temperatures. It is thus considered that when a gas-phase reaction is performed at a high temperature as described in Patent Literature 1, the CF₂=CF₂ used as a starting material is thermally decomposed, which produces lower fluorocarbons as by- products and also causes carbonization reactions, thus failing to produce the desired fluorine-containing propene compound with high selectivity.

Patent Literature 2 (PTL 2) listed below describes a process comprising reacting CF₂=CF₂ and CH₃CI in a liquid phase in the presence of cesium fluoride. However, when such conditions are used, the reaction produces pentafluoropropane in a high yield, i.e., about 90%, and fails to produce the desired CF₃CF=CI^ of the present invention.

Citation List

Patent Literature

PTL 1: U.S. Patent No. 2,931,840

PTL 2: U.S. Patent No. 3,381,042

Non Patent Literature

NPL 1: J. Phys. Chem. , 1968, 72, 3463

Summary of Invention Technical Problem A principal object of the present invention is to provide a novel process for producing a fluorine-containing propene compound, such as CF₃CF=CH₂, with high selectivity in a comparatively simple manner.

Solution to Problem

To achieve the above object, the present inventors have carried out extensive research. As a result, the inventors found that when tetrafluoroethylene is reacted with methyl halide in the presence of a specific catalyst, CF3CF=CH₂ can be produced with high selectivity by a single-step reaction under comparatively low temperature conditions, i.e., at 650°C or less. The present invention has been accomplished based on this finding.

More specifically, the present invention provides the following process for producing a fluorine-containing propene compound.

1. A process for producing a fluorine-containing propene compound represented by the formula CF₃CF=CYZ wherein Y and Z are the same or different and each represent a hydrogen atom- or a halogen atom, the process comprising reacting a compound represented by the formula CF₂=CF₂ with a halogen-containing compound represented by the formula CHXYZ wherein X is chlorine, bromine, or iodine, and Y and Z are as defined above, in the presence of at least one component selected from the group consisting of metal halides and metal oxides. 2. The process according to item 1, wherein the metal halide is a compound represented by the formula M^A _nM^B _mF_x wherein M^A is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Au, or NH₄; M^B is B, Al, Ga, In, P, As, Sb, Bi, Zr, Ti, or Si; n is an integer of 0 to 4; m is an integer of 0 to 4; n and m are not 0 at the same time; and x is an integer of 1 to 10; and the metal oxide is a compound represented by the formula M^c _kM^DiO_y wherein M^c is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Ce, La, or Au; and M^D is B, Al, Ga, In, N, P, As, Sb, Bi, Zr, Ti, C, Si, Sn, Co, Fe, Ni, Cu, Cr, Mn, Mo, V, W, S, Th, or NH₄; k is an integer of 0 to 4; 1 is an integer of 0 to 4; k and 1 are not 0 at the same time; and y is an integer of 1 to 20.

3. The process according to item 1 or 2, wherein the metal halide is at least one compound selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and the metal oxide is at least one compound selected from the group consisting of alkali metal oxides and alkaline earth metal oxides.

4. The process according to any one of items 1 to 3, wherein the reaction is performed at a temperature of 0⁰C to 65O⁰C in a gas or liquid phase at atmospheric or increased pressure.

5. The process according to any one of items 1 to 4 wherein the halogen-containing compound represented by the formula CHXYZ, wherein X is chlorine, bromine, or iodine, and Y and Z are the same or different and each represent a hydrogen atom or a halogen atom, is CH₃X wherein X is as defined above.

In the process of the present invention, tetrafluoroethylene represented by the formula CF₂=CF₂ and a halogen-containing compound represented by the formula CHXYZ are used as starting materials. In the above formula, X is chlorine, bromine, or iodine, and Y and Z are the same or different and each represent a hydrogen atom or a halogen atom. Examples of halogen atoms include F, Cl, Br, and I. Examples of halogen- containing compounds represented by CHXYZ include CH₃Cl, CH₃Br, CH₃I, CH₂Cl₂, CH₂ClF, CH₂ClBr, CH₂FBr, CH₂Br₂, CH₂I₂, CHCl₃, CHCl₂F, CHClF₂, CHF₂Br, CHFBr₂, CHCl₂Br, CHClBr₂, CHF₂I, CHI₃, and the like. For example, to produce a compound represented by the formula CF₃CF₂=CH₂, compounds represented by the formula CH₃X wherein X is as defined above may be used. According to the process of the present invention, it is necessary that the tetrafluoroethylene represented by the formula CF₂=CF₂ be reacted with a halogen-containing compound represented by the formula CHXYZ in the presence of at least one catalyst component selected from the group consisting of metal halides and metal oxides.

Among the catalyst components, examples of metal halides include compounds represented by the formula M^A _nM^B _mF_x. In the formula, M^A is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Au, or NH₄; M^B is B, Al, Ga, In, P, As, Sb, Bi, Zr, Ti, or Si; n is an integer of 0 to 4; m is an integer of 0 to 4; n and m are not 0 at the same time; and x is an integer of 1 to 10. Specific examples of metal halides represented by the above formula include NaF, KF, LiF, RbF, CsF, NH₄F, CaF₂, MgF₂, BaF₂, SrF₂, ZnF₂, SnF₂, AlF₃, SbF₃, PbF₂, NiF₂, CrF₃, Na₂SiF₆, K₂SiF₆, Li₂SiF₆, MgSiF₆, CaSiF₆, BaSiF₆, ZnSiF₆,

Na₂TiF₆, K₂TiF₆, Li₂TiF₆, MgTiF₆, CaTiF₆, BaTiF₆, ZnTiF₆, Na₂ZrF₆, K₂ZrF₆, Li₂ZrF₆, MgZrF₆, CaZrF₆, BaZrF₆, ZnZrF₆, Na₃AlF₆, K₃AlF₆, Li₃AlF₆, Na₃FeF₆, K₃FeF₆, Li₃FeF₆, NaSbF₆, KSbF₆, LiSbF₆, NaAsF₆, KAsF₆, LiAsF₆, NaPF₆, KPF₆, LiPF₆, NaBF₄, KBF₄, LiBF₄, and the like. Among these metal halides, NaF, KF, LiF, CsF, NH₄F, CaF₂, MgF₂, BaF₂, ZnF₂, NiF₂, CrF₃, Na₃AlF₆, K₃AlF₆, Na₃FeF₆, K₃FeF₆, Na₂SiF₆, K₂SiF₆, Li₂SiF₆, MgSiF₆, CaSiF₆, Na₂ZrF₆, K₂ZrF₆, Li₂ZrF₆, MgZrF₆, CaZrF₆, Na₂TiF₆, K₂TiF₆, Li₂TiF₆, MgTiF₆, CaTiF₆, NaPF₆, LiPF₆, NaBF₄, LiBF₄, etc. are preferable from the viewpoints of the reactivity, ease of handling, and cost. Alkali metal fluorides and alkaline earth metal fluorides are particularly preferable.

Examples of metal oxides include compounds represented by the formula M^M^O_y. In the formula, M^c is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Ce, La, or Au; M^D is B, Al, Ga, In, N, P, As, Sb, Bi, Zr, Ti, C, Si, Sn, Co, Fe, Ni, Cu, Cr, Mn, Mo, V, W, S, Th, or NH₄; k is an integer of 0 to 4; 1 is an integer of 0 to 4; k and 1 are not 0 at the same time; and y is an integer of 1 to 20. Specific examples of metal oxides represented by the above formula include CaO, MgO, BaO, ZnO, SrO, BeO, Al₂O₃, SiO₂, ZrO₂, TiO₂, CeO₂, MoO₃, NiO, Fe₂O₃, Bi₂O₃, B₂O₃, ThO₂, La₂O₃, CuO, Cr₂O₃, In₂O₃, SnO₂, WO₃, V₂Os, MnO, FeO, complex oxides thereof, and the like. Among these metal oxides, CaO, MgO, BaO, ZnO, SnO₂, FeO, Bi₂O₃, MoO₃, SrO, BeO, Al₂O₃, SiO₂, ZrO₂, TiO₂, CeO₂, Fe₂O₃, Bi₂O₃, MnO, FeO, and complex oxides thereof are preferable from the viewpoints of reactivity and cost. Alkali metal oxides and alkaline earth metal oxides are particularly preferable .

The metal halides and metal oxides can be used singly or as a mixture of two or more kinds. It is particularly preferable to use as the catalyst a metal halide or a mixture of a metal halide with a metal oxide. When a metal halide and a metal oxide are used as a mixture, the mixing ratio is such that the amount of metal halide is preferably 5 wt.% or more, based on the total amount of the metal halide and metal oxide used. The catalyst may be supported on a carrier. There is no specific limitation on the carrier as long as it is stable during the reaction. The carrier can be suitably selected from known carriers, such as activated carbon, metallic aluminum, silica, alumina, zirconia, magnesia, titania, celite, zeolite, silicon carbide, diatomaceous earth, and the like.

There is no specific limitation on the amount of the catalyst component, i.e., at least one component selected from the group consisting of metal halides and metal oxides. The amount of catalyst component is preferably about 0.0001 to about 100 equivalents, based on one equivalent of the total amount of tetrafluoroethylene fed.

The process of the present invention can be carried out, for example, in the presence of a catalyst component as mentioned above in a gas or liquid phase. To carry out the reaction in a gas phase, a fixed bed gas-phase reaction, a fluidized bed gas-phase reaction, or like reaction system can be applied. The reaction can proceed, for example, by feeding tetrafluoroethylene and a halogen-containing compound in gas states to a gas phase reactor containing a catalyst fed in a fixed bed. The kinds of starting materials, molar ratio of reactants, kind and amount of catalyst used, reaction temperature, pressure, and other specific reaction conditions can be suitably selected according to the kind of CF₃CF=CYZ to be produced. The feeding ratio of the halogen-containing compound and tetrafluoroethylene is such that the amount of halogen- containing compound represented by CHXYZ is preferably about 0.1 to about 100 moles, and more preferably about 0.2 to about 20 moles, per mole of tetrafluoroethylene. If the amount of halogen- containing compound is too small, a low yield of CF₃CF=CYZ results. If the amount of halogen-containing compound is too large, separation becomes difficult.

When the process of the present invention is performed in a gas phase, the use of a specific catalyst as mentioned above allows the reaction to proceed at a temperature to about 0 to about 65O⁰C. Thus, the reaction can proceed at a lower temperature than in conventional processes, thus inhibiting thermal decomposition of tetrafluoroethylene and producing a fluorine-containing propene compound represented by the formula CF₃CF=CYZ with high selectivity. In particular, a reaction temperature of about 200 to about 60O⁰C is preferable to enhance the conversion of tetrafluoroethylene and the selectivity of a fluorine-containing propene compound represented by the formula CF₃CF=CYZ . Although there is no specific limitation on the reaction pressure in the gas phase reaction, the reaction is preferably carried out at atmospheric pressure to an increased pressure of about 1 MPa. It is particularly preferable to select the pressure conditions under which the starting materials present in the reaction system are not liquefied in the system.

The contact time is usually 0.1 to 300 seconds, and preferably about 1 to about 180 seconds. An excessively short reaction time may result in a low conversion, whereas an excessively long reaction time may result in large amounts of carbides and by-products.

The gas phase reaction between tetrafluoroethylene and a halogen-containing compound, if performed in the presence of moisture, can increase the selectivity of a fluorine-containing propene compound represented by CF₃CF=CYZ. The gas phase reaction is allowed to proceed in the presence of moisture, for example, in the following manner. The starting tetrafluoroethylene and halogen-containing compound in gas states are bubbled into water, and the resulting mixture is fed into the gas phase reactor. Alternatively, a vaporizing chamber into which water is supplied is mounted upstream of the gas phase reactor.

Further, the catalyst can be activated by supplying hydrogen fluoride to the reactor during or after the reaction of the tetrafluoroethylene and halogen-containing compound. The desired fluorine-containing propene compound represented by the formula CFaCF=CYZ can be thereby continuously obtained with high selectivity.

When the process of the present invention is performed in a liquid phase, a reaction temperature of about 50°C to about 300⁰C is preferable. The pressure during the reaction is preferably atmospheric to an increased pressure of about 5 MPa.

The reaction time is usually about 0.1 to about 10,000 minutes, and preferably about 10 to about 1,000 minutes in terms of the residence time in the reactor.

The reaction in a liquid phase can proceed even in the absence of solvents. The reaction may be carried out using solvents such as tetrahydrofuran, t-butylrαethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, dioxane, dimethoxymethane, 1,2-dimethoxyethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 4-methylpentan-2-one, acetone, 2-butanone, 2- pentanone, 2-hexanone, 2-heptanone, cyclohexanone, methylamino ketone, ethyl acetate, methyl acetate, propyl acetate, butyl acetate, methyl butyrate, ethyl butylate, butyl butyrate, methyl lactate, ethyl lactate, methyl formate, ethyl formate, propyl formate, γ-butyrolactone, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide, and the like.

Advantageous Effects of the Invention

According to the process of the present invention, a fluorine-containing propene compound that is an excellent candidate as an alternative solvent can be produced with high selectivity by a single-step reaction using a comparatively inexpensive tetrafluoroethylene as a starting material.

Thus, the process of the present invention is an industrially advantageous method for producing a fluorine- containing propene compound.

Description of Embodiments

The present invention will be described below in more detail with reference to Examples.

Example 1 As a catalyst, 20 ml of NaF in the form of pellets was fed into a gas phase reactor composed of a cylindrical reaction tube (made of SUS316, 1.0 cm in diameter, 30 cm long) equipped with an electric furnace. While tetrafluoroethylene (20 mL/min) and CH₃CI (40 mL/min) (each amount being expressed as a flow rate in a standard state) were fed into this reactor, the temperature of the reaction tube was maintained at 45O⁰C.

The gas composition flowing out of the reaction tube was analyzed by gas chromatography. The analysis shows that the conversion of tetrafluoroethylene (TFE) was 7.9%; the obtained composition contained CF₃CF=CH₂ (4.5 mole %) , C₃F₇H (1.0 mole %) , and carbon and the like (2.4 mole %); and the selectivity of CF₃CF=CH₂ (HFO-1234yf) was 60%. Table 1 below shows the results.

Examples 2 to 7 The same gas phase reactor as in Example 1 was used.

The catalysts shown below in Table 1 were formed into pellets, and 20 ml of each was fed into the reactor.

While tetrafluoroethylene (20 mL/min) and CH₃Cl (40 mL/min) (each amount being expressed as a flow rate in a standard state) were fed into the reactor, the reaction was allowed to proceed at a reaction tube temperature, as shown below in Table 1.

In Examples 3, 4, 6, and 7, the tetrafluoroethylene and CH₃Cl were fed into the reactor after immersed in water. Table 1 shows the assay results of the gas compositions obtained in the same manner as in Example 1.

Examples 8 and 9

The same gas phase reactor as in Example 1 was used. The catalysts shown below in Table 1 were formed into pellets, and 20 ml of each was fed into the reactor.

Tetrafluoroethylene (20 mL/min) and CH₃I were fed with nitrogen (30 mL/min) into the reactor in such a proportion that the amount of CH₃I was twice that of tetrafluoroethylene. The reaction was allowed to proceed at a reaction tube temperature, as shown below in Table 1. Table 1 shows the assay results of the gas compositions obtained in the same manner as in Example 1.

Examples 10 and 11

While tetrafluoroethylene (20 inL/min) and CH₃Br (40 mL/min) were fed into the reactor, the reaction was allowed to proceed at a reaction tube temperature, as shown below in Table 1. Table 1 shows the assay results of the gas compositions obtained in the same manner as in Example 1.

Table 1

Example Catalyst Reaction Contact Wet TEE HFO-1234yf No . temperature time treatment conversion selectivity (⁰C) (sec) (%) (%) 1 NaF 450 20 Not done 8 60

2 NaF 502 20 Not done 22 35

3 NaF 464 20 Done 2 >98

4 NaF 632 20 Done 33 62

5 MgO 465 15 Not done 17 28

6 30%KF/CaF₂ 461 15 Done 4 >98

7 30%KF/CaF₂ 519 15 Done 26 60

8 NaF 465 13 Not done 10 87

9 NaF 519 13 Not done 35 32

10 95% CsF/Graphite 456 20 Done 14 79

11 95% CsF/Graphite 498 20 Done 34 58

Claims

[Claim 1] A process for producing a fluorine-containing propene compound represented by the formula CF₃CF=CYZ wherein Y and Z are the same or different and each represent a hydrogen atom or a halogen atom, the process comprising reacting a compound represented by the formula CF₂=CF₂ with a halogen-containing compound represented by the formula CHXYZ wherein X is chlorine, bromine, or iodine, and Y and Z are as defined above, in the presence of at least one component selected from the group consisting of metal halides and metal oxides.

[Claim 2] The process according to claim 1, wherein the metal halide is a compound represented by the formula M^A _nM^B _mF_x wherein M^a is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Au, or NH₄; M^B is B, Al, Ga, In, P, As, Sb, Bi, Zr, Ti,- or Si; n is an integer of 0 to 4; m is an integer of 0 to 4; n and m are not 0 at the same time; and x is an integer of 1 to 10; and the metal oxide is a compound represented by the formula M^C _kM^DiO_y wherein M^c is an alkali metal, an alkaline earth metal, Cr, Mn, Fe, Co, Ni, Zn, Cu, Pd, Ag, Pt, Ce, La, or Au; and M^D is B, Al, Ga, In, N, P, As, Sb, Bi, Zr, Ti, C, Si, Sn, Co, Fe, Ni, Cu, Cr, Mn, Mo, V, W, S, Th, or NH₄; k is an integer of 0 to 4; 1 is an integer of 0 to 4; k and 1 are not 0 at the same time; and y is an integer of 1 to 20.

[Claim 3] The process according to claim 1 or 2, wherein the metal halide is at least one compound selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and the metal oxide is at least one compound selected from the group consisting of alkali metal oxides and alkaline earth metal oxides.

[Clairα 4] The process according to any one of claims 1 to 3, wherein the reaction is performed at a temperature of O⁰C to 65O⁰C in a gas or liquid phase at atmospheric or increased pressure.

[Claim 5] The process according to any one of claims 1 to 4 wherein the halogen-containing compound represented by the formula CHXYZ, wherein X is chlorine, bromine, or iodine, and Y and Z are the same or different and each represent a hydrogen atom or a halogen atom, is CH₃X wherein X is as defined above.