METHOD FOR PRODUCING FLUOROOLEFIN

Abstract

The present disclosure provides a method for producing fluoroolefin represented by formula (1): CX.sup.1X.sup.2=CX.sup.3X.sup.4, wherein X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are the same or different, and represent a hydrogen atom or a fluorine atom, with high selectivity. Specifically, the present disclosure is a method for producing a fluoroolefin represented by formula (1) described above, the method comprising a dehydrofluorination step of bringing a fluorocarbon represented by formula (2): CX.sup.1X.sup.2FCX.sup.3X.sup.4H, wherein X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are as defined above, into contact with a metal catalyst to perform dehydrofluorination, the dehydrofluorination step being performed in the gas phase in the presence of water, the concentration of the water being less than 500 ppm relative to the fluorocarbon represented by formula (2).

Claims

1. A method for producing a fluoroolefin represented by formula (1): CX.sup.1X.sup.2═CX.sup.3X.sup.4, wherein X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are the same or different, and represent a hydrogen atom or a fluorine atom, the method comprising a dehydrofluorination step of bringing a fluorocarbon represented by formula (2): CX.sup.1X.sup.2FCX.sup.3X.sup.4H, wherein X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are as defined above, into contact with a metal catalyst to perform dehydrofluorination, the dehydrofluorination step being performed in the gas phase in the presence of water, the concentration of the water being less than 500 ppm relative to the fluorocarbon represented by formula (2).

2. The production method according to claim 1, wherein the fluoroolefin represented by formula (1) is at least one member selected from the group consisting of 1,2-difluoroethylene (HFO-1132), 1,1-difluoroethylene (HFO-1132a), and trifluoroethylene (HFO-1123).

3. The production method according to claim 1, wherein the fluorocarbon represented by formula (2) is at least one member selected from the group consisting of 1,1,1-trifluoroethane (HFC-143a), 1,1,2-trifluoroethane (HFC-143), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,1,2-tetrafluoroethane (HFC-134a).

4. The production method according to claim 1, wherein the dehydrofluorination step is performed in the presence of an oxidizing agent.

5. The production method according to claim 4, wherein the oxidizing agent is oxygen.

6. The production method according to claim 5, wherein the concentration of the oxygen is 0.01 to 21 mol % relative to the fluorocarbon represented by formula (2).

7. The production method according to claim 1, wherein the metal catalyst is at least one member selected from the group consisting of chromium oxide, fluorinated chromium oxide, chromium fluoride, aluminum oxide, fluorinated aluminum oxide, aluminum fluoride, iron oxide, fluorinated iron oxide, iron fluoride, nickel oxide, fluorinated nickel oxide, nickel fluoride, magnesium oxide, fluorinated magnesium oxide, and magnesium fluoride.

8. The production method according to claim 1, wherein the dehydrofluorination step is performed at a temperature of 300 to 600° C.

9. The production method according to claim 1, wherein, in the dehydrofluorination step, the contact time (W/F.sub.0) between the fluorocarbon represented by formula (2) and the metal catalyst is 10 g.Math.sec/mL to 200 g.Math.sec/mL.

10. The production method according to claim 1, wherein the dehydrofluorination step is performed in the presence of an inert gas and/or hydrogen fluoride.

11. The production method according to claim 10, wherein the dehydrofluorination step is performed in the presence of an inert gas, and the inert gas is at least one member selected from the group consisting of nitrogen, helium, argon, and carbon dioxide.

12. The production method according to claim 1, comprising a hydrogenation step of subjecting a fluoroolefin represented by formula (3): CX.sup.5X.sup.6═CX.sup.7X.sup.8, wherein X.sup.5, X.sup.6, X.sup.7, and X.sup.8 are the same or different, and represent a hydrogen atom, a fluorine atom, or a chlorine atom; and at least one of X.sup.5, X.sup.6, X.sup.7, and X.sup.8 represents a fluorine atom, to a hydrogenation reaction to obtain the fluorocarbon represented by formula (2), wherein the fluorocarbon represented by formula (2) is at least one member selected from the group consisting of 1,1,2-trifluoroethane (HFC-143) and 1,1,2,2-tetrafluoroethane (HFC-134).

13. The production method according to claim 12, wherein the fluoroolefin represented by formula (3) is chlorotrifluoroethylene (CTFE).

Description

EXAMPLES

[0099] The present disclosure will be specifically described below with reference to Examples, Comparative Examples, and Reference Examples. However, the present disclosure is not limited to these Examples.

Example 1

[0100] SUS piping (outer diameter: ½ inch) was filled with 10 g of chromium oxide mainly containing Cr.sub.2O.sub.3 as a catalyst. As a pretreatment for using the catalyst in a dehydrofluorination reaction, anhydrous hydrogen fluoride was passed through the reactor, and a fluorination treatment was conducted by setting the temperature of the reactor to 300 to 460° C. The fluorinated chromium oxide was taken out and used in the dehydrofluorination reaction. The BET specific surface area of the fluorinated chromium oxide was 75 m.sup.2/g.

[0101] 10 g of fluorinated chromium oxide (fluorinated chromium oxide) was added as a metal catalyst to SUS piping (outer diameter: ½ inch), which was a reactor. After drying for 2 hours under nitrogen atmosphere at 200° C., HFC-143 was passed through the reactor as a raw material compound in such a manner that the pressure was atmospheric pressure and the contact time (W/F.sub.0) between HFC-143 and the fluorinated chromium oxide was 40 g.Math.sec/mL.

[0102] The concentration of water in the raw material compound was measured using a Karl Fischer moisture analyzer (produced by Mitsubishi Chemical Analytic Tech Co., Ltd., trade name CA-200 trace moisture measurement device), and was 10 ppm.

[0103] Further, oxygen was added to the reactor in such a manner that the concentration of oxygen was 15 mol % relative to HFC-143, and heating was performed at 350° C. to start a dehydrofluorination reaction.

[0104] One hour after the start of the dehydrofluorination reaction, the distillate that passed through a scrubber was collected. Thereafter, mass spectrometry was performed according to the gas chromatography/mass spectrometry (GC/MS) method by using a gas chromatography device (produced by Shimadzu Corporation; trade name: GC-2014), and structural analysis according to NMR spectroscopy was performed using an NMR device (produced by =14 trade name: 400YH).

[0105] The results of the mass spectrometry and structural analysis confirmed the generation of (E)-HFO-1132 and (Z)-HFO-1132.

[0106] The conversion of HFC-143 was 68 mol %. The total yield (selectivity) of (E)-HFC-1132 and (Z)-HFO-1132 was 91 mol %. The selectivity of (E)-HFO-1132 was 18 mol %, and the selectivity of (Z)-HFO-1132 was 73 mol %. The results are shown in Table 1 below.

Example 2

[0107] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the concentration of water in HFC-143 when measured with a Karl Fischer moisture analyzer was 300 ppm. The results are shown in Table 1 below.

Comparative Example 1

[0108] SUS piping (outer diameter: ½ inch) was filled with 10 g of chromium oxide mainly containing Cr.sub.2O.sub.3 as a catalyst. As a pretreatment for using the catalyst in a dehydrofluorination reaction, anhydrous hydrogen fluoride was passed through the reactor, and a fluorination treatment was conducted by setting the temperature of the reactor to 300 to 460° C. The fluorinated chromium oxide was taken out and used in the dehydrofluorination reaction. The BET specific surface area of the fluorinated chromium oxide was 75 m.sup.2/g.

[0109] 10 g of fluorinated chromium oxide (fluorinated chromium oxide) was added as a metal catalyst to SUS piping (outer diameter: ½ inch), which was a reactor. After drying for 2 hours under nitrogen atmosphere at 200° C., HFC-143 was passed through the reactor as the raw material compound in such a manner that the pressure was atmospheric pressure and the contact time (W/F.sub.0) between HFC-143 and fluorinated chromium oxide was 40 g.Math.sec/mL.

[0110] The concentration of water in the raw material compound was measured with a Karl Fischer moisture analyzer, and was 500 ppm.

[0111] Further, oxygen was added as an oxidizing agent to the reactor in such a manner that the concentration of oxygen was 15 mol° relative to HFC-143, and heating was performed at 350° C. to start a dehydrofluorination reaction.

[0112] One hour after the start of the dehydrofluorination reaction, the distillate passed through a scrubber was collected. Thereafter, mass spectrometry was performed according to the gas chromatography/mass spectrometry (GC/MS) method by using a gas chromatography device (produced by Shimadzu Corporation; trade name: GC-2014), and structural analysis according to NMR spectroscopy was performed using an NMR device (produced by JEOL; trade name: 400YH).

[0113] The results of the mass spectrometry and structural analysis confirmed the generation of (E)-HFO-1132 and (Z) -HFO-1132.

[0114] The conversion of HFC-143 was 42 mol %. The total yield (selectivity) of (E)-HFO-1132 and (Z)-HFO-1132 was 89 mol %. The selectivity of (E)-HFO-1132 was 8 mol %, and the selectivity of (Z)-HFO-1132 was 81 mol %. The results are shown in Table 1 below.

Example 3

[0115] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the concentration of water in HFC-143 when measured with a Karl Fischer moisture analyzer was 10 ppm, and fluorinated chromium oxide, which was a metal catalyst, was dried under nitrogen atmosphere at 400° C. for 2 hours. The results are shown in Table 1 below.

Example 4

[0116] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the concentration of oxygen was set to 0 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was set to 400° C. The results are shown in Table 2 below.

Example 5

[0117] The dehydrofluorination reaction was continuously performed from Example 4, and 3 hours after the start of the dehydrofluorination reaction, mass spectrometry and structural analysis were performed in the same manner as in Example 1. The results are shown in Table 2 below.

Example 6

[0118] The dehydrofluorination reaction was continuously performed from Example 4, and 10 hours after the start of the dehydrofluorination reaction, mass spectrometry and structural analysis were performed in the same manner as in Example 1. The results are shown in Table 2 below.

Example 7

[0119] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the reaction temperature when the dehydrofluorination reaction was started was changed to 400° C. The results are shown in Table 2 below.

Example 8

[0120] The dehydrofluorination reaction was continuously performed from Example 7, and 3 hours after the start of the dehydrofluorination reaction, mass spectrometry and structural analysis were performed in the same manner as in Example 1. The results are shown in Table 2 below.

Example 9

[0121] The dehydrofluorination reaction was continuously performed from Example 7, and 10 hours after the start of the dehydrofluorination reaction, mass spectrometry and structural analysis were performed in the same manner as in Example 1. The results are shown in Table 2 below.

Example 10

[0122] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the concentration of oxygen was set to 0 mol % relative to HFC-143. The results are shown in Table 3 below.

Example 11

[0123] SUS piping (outer diameter: ½ inch) was filled with 10 g of chromium oxide mainly containing Cr.sub.2O.sub.3 calcined at 700° C. or more as a catalyst. As a pretreatment for using the catalyst in a dehydrofluorination reaction, anhydrous hydrogen fluoride was passed through the reactor, and a fluorination treatment was conducted by setting the temperature of the reactor to 300 to 460° C. The fluorinated chromium oxide was taken out and used in the dehydrofluorination reaction. The BET specific surface area of the fluorinated crystallized chromium oxide was 15 m.sup.2/g.

[0124] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 g of the fluorinated crystallized chromium oxide was used as a metal catalyst, the oxygen concentration was 0 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was 600° C. The results are shown in Table 3 below.

Example 12

[0125] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 g of the fluorinated crystallized chromium oxide prepared in Example 12 was used as a metal catalyst, the oxygen concentration was set to 0 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was changed to 580° C. The results are shown in Table 3 below.

Example 13

[0126] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 g of the fluorinated crystallized chromium oxide prepared in Example 12 was used as a metal catalyst, the oxygen concentration was set to 5 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was changed to 400° C. The results are shown in Table 3 below.

Example 14

[0127] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 g of the fluorinated crystallized chromium oxide prepared in Example 12 was used as a metal catalyst, the oxygen concentration was set to 10 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was changed to 400° C. The results are shown in Table 3 below.

Example 15

[0128] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 g of the fluorinated crystallized chromium oxide prepared in Example 12 was used as a metal catalyst, and the reaction temperature when the dehydrofluorination reaction was started was changed to 400° C. The results are shown in Table 3 below.

Example 16

[0129] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the contact time (W/F.sub.0) was 60 g.Math.sec/mL, and the reaction temperature when the dehydrofluorination reaction was started was 400° C. The results are shown in Table 3 below.

Example 17

[0130] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that the contact time (W/F.sub.0) was 100 g.Math.sec/mL, and the reaction temperature when the dehydrofluorination reaction was started was 400° C. The results are shown in Table 3 below.

Example 18

[0131] SUS piping (outer diameter: ½ inch) was filled with 10 g of Al.sub.2O.sub.3 (produced by JGC Catalysts and Chemicals Ltd., N612N) as a catalyst. As a pretreatment for using the catalyst in a dehydrofluorination reaction, anhydrous hydrogen fluoride was passed through the reactor, and a fluorination treatment was conducted by setting the temperature of the reactor to 300 to 460° C. The fluorinated aluminum oxide was taken out and used in the dehydrofluorination reaction. The BET specific surface area of fluorinated aluminum oxide was 90 m.sup.2/g.

[0132] A dehydrofluorination reaction, mass spectrometry, and structural analysis were performed in the same manner as in Example 1 except that 10 a of the fluorinated aluminum oxide was used as a metal catalyst, the oxygen concentration was set to 0 mol % relative to HFC-143, and the reaction temperature when the dehydrofluorination reaction was started was set to 400° C. The results are shown in Table 3 below.

[0133] Example 19

[0134] 10 g of fluorinated chromium oxide (fluorinated chromium oxide) prepared in Example 1 was added as a metal catalyst to SUS piping (outer diameter: ½ inch), which. Was a reactor. After drying for 2 hours under nitrogen atmosphere at 200° C., HFC-134a was passed through the reactor as the raw material compound in such a manner that the pressure was atmospheric pressure and the contact time (W/F.sub.0) between HFC-134a and the fluorinated chromium oxide was 60 g.Math.sec/mL.

[0135] The concentration of water in the raw material compound was measured with a Karl Fischer moisture analyzer (produced by Mitsubishi Chemical Analytic Tech Co., Ltd.; trade name: CA-200 trace moisture measurement device), and was 10 ppm.

[0136] Further, oxygen used as an oxidizing agent was added to the reactor in such a manner that the concentration of oxygen was 15 mol % relative to HFC-134a, and heating was performed at 400° C. to start a dehydrofluorination reaction.

[0137] One hour after the start of the dehydrofluorination reaction, the distillate passed through a scrubber was collected. Thereafter, mass spectrometry was performed according to the gas chromatography/mass spectrometry (GC/MS) method by using a gas chromatography device (produced by Shimadzu Corporation; trade name: GC-2014), and structural analysis according to NKR spectroscopy was performed using an NMR device (produced by JEOL; trade name: 400YH). The results of mass spectrometry and structural analysis confirmed generation of HFO-1123.

[0138] The conversion of HFC-134a was 53 molt. The yield (selectivity) of HFO-1123 was 85 molt. The results are shown in Table 3.

Reference Example 1

[0139] CTFE and hydrogen were passed through SUS piping (outer diameter: ½ inch), which was a reactor, and a hydrogenation reaction was performed according to a known method. One hour after the start of the hydrogenation reaction, the distillate passed through a scrubber was collected. Thereafter, mass spectrometry was performed according to the gas chromatography/mass spectrometry (GC/MS) method by using a gas chromatography device (produced by Shimadzu Corporation; trade name: GC-2014), and structural analysis according to NMR spectroscopy was performed using an NMR device (produced by JEOL; trade name: 400YH). The results of mass spectrometry and structural analysis confirmed that HFC-143 was generated by the hydrogenation reaction.

[0140] Tables 1 to 3 show the results of the Examples and the Comparative Examples.

[0141] In Tables 1 to 3, the contact time (W/F.sub.0 means the rate of the raw material gas that is passed through, i.e., the time in which the metal catalyst is in contact with the raw material compound.

[0142] The reaction duration (h) in Table 2 means the time from the start of the flow of the raw material gas.

[0143] Regarding the oxygen concentration (molt) in Tables 2 and 3, the expression “n.d.” means that the oxygen concentration measured using an oxygen analyzer (produced by Teldyne Co., Ltd.; trade name: 311 Trace Oxygen Analyzer) was less than the detection limit. “n.d.” means “not detected.”

TABLE-US-00001 TABLE 1 Example/ Concentration Amount of Reaction Oxygen HFC-43 (E)-1132 (Z)-1132 Comparative of water metal catalyst W/Fc temperature concentration conversion selectivity selectivity Example (ppm) (g) (g .Math. sec/mL) (° C.) (mol %) (mol %) (mol %) (mol %) Example1 10 10 40 350 15 68 18 73 Example2 300 10 40 350 15 50 10 80 Comparative 500 10 40 350 15 4 8 81 Example1 Example3 10 10 40 350 15 69 15 77 indicates data missing or illegible when filed

TABLE-US-00002 TABLE 2 Reaction Concentration Amount of Reaction Oxygen HFC-143 (E)-1132 (Z)-1132 duration of water metal catalyst W/ temperature concentration conversion selectivity selectivity Example (h) (ppm) (g) (g .Math. sec/mL) (° C.) (mol %) (mol %) (mol %) (mol %) Example 4 1 10 10 40 400 n.d. 89 30 60 Example 5 3 10 10 40 400 n.d. 87 21 75 Example 6 10 10 10 40 400 n.d. 52 10 88 Example 7 1 10 10 40 400 15 8 29 59 Example 8 3 10 10 40 400 15 87 27 60 Example 9 10 10 10 40 400 15 88 25 6 indicates data missing or illegible when filed

TABLE-US-00003 TABLE 3 Concentration Amount of Reaction Oxygen HFC-143 (E)-1132 (Z)-1132 of water metal catalyst W/F temperature concentration conversion selectivity selectivity Example (ppm) (g) (g .Math. sec/mL) (° C.) (mol %) (mol %) (mol %) (mol %) Example 10 10 10 40 350 n.d. 68 24 70 Example 11 10 10 40 00 n.d. 85 27 58 Example 12 10 10 40 0 n.d. 50 16 69 Example 13 10 10 40 400  5 80 13 80 Example 14 10 10 40 400 10 4 15 79 Example 15 10 10 40 400 15 8 19 74 Example 16 10 10 0 400 15 93 8 63 Example 17 10 10 100 400 15 94 31 58 Example 18 10 10 40 400 n.d. 84 32 60 Concentration Amount of Reaction Oxygen HFC-134a HFO-1123 of water metal catalyst W/F temperature concentration conversion selectivity Example (ppm) (g) (g .Math. sec/mL) (° C.) (mol %) (mol %) (mol %) Example 19 10 10 0 400 15 53 85 indicates data missing or illegible when filed