PREPARATION METHOD OF TRANS-1,1,1,4,4,4-HEXAFLUORO-2-BUTENE

Abstract

The present invention belongs to the technical field of fluorine chemical industry, specifically relates to a preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene, comprising the following steps: preheating trans-2-ethoxy-1,1,1,4,4,4-hexafluoro-2-butene, mixing with hydrogen, reacting to obtain trans-1,1,1,4,4,4-hexafluoro-2-butene under the action of a catalyst. The selectivity of trans 1,1,1,4,4,4-hexafluoro-2-butene prepared by the preparation method of the present invention can reach 99%, the preparation method adopts moderate reaction temperature and produces less three wastes. The trans 1,1,1,4,4,4-hexafluoro-2-butene prepared by the preparation method has great application value in electric power, electrical appliances and electronics industries.

Claims

1. A preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene, comprising the following steps: preheating trans-2-ethoxy-1,1,1,4,4,4-hexafluoro-2-butene, then mixing it with hydrogen, and reacting in the presence of a catalyst to obtain trans-1,1,1,4,4,4-hexafluoro-2-butene; the catalyst comprises an aluminum-magnesium composite oxide and a group VIII transition metal.

2. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, wherein a molar ratio of the trans-2-ethoxy-1,1,1,4,4,4-hexafluoro-2-butene to the hydrogen is 1:(1-5).

3. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, wherein the aluminum-magnesium composite oxide has a BET surface area of 200-500 m2/g.

4. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, wherein the group VIII transition metal is one or two selected from the group consisting of Ru, Ni and Co.

5. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, wherein the group VIII transition metal has a mass content of 0.5-10.0 wt % of a total mass of the catalyst.

6. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, wherein the aluminum-magnesium composite oxide is prepared by the following steps: taking an aluminum-containing compound and a magnesium-containing compound as raw materials, adding polyethylene glycol or an organic amine as a stencil, and synthesizing the aluminum-magnesium composite oxide by hydrothermal, solvothermal or dry gel conversion methods.

7. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 6, comprising at least one of the following (1)-(2): (1) the aluminum-containing compound comprises at least one selected from the group consisting of aluminum hydroxide, pseudo-boehmite, hydrated alumina, and aluminum isopropanol; (2) the magnesium-containing compound comprises at least one selected from the group consisting of magnesium oxide, magnesium nitrate, magnesium acetate and magnesium metal.

8. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 1, comprising at least one of the following (1)-(3): (1) the reacting is carried out at a temperature of 150-250 C.; (2) the reacting is carried out at a space velocity of 1.0-5.0 h.sup.1; (3) the reacting is carried out under a pressure of 0.2-2.0 MPa.

9. The preparation method of trans-1,1,1,4,4,4-hexafluoro-2-butene according to claim 8, comprising at least one of the following (1)-(3): (1) the reacting is carried out at a temperature of 180-225 C.; (2) the reacting is carried out at a space velocity of 1.5-2.5 h.sup.1; (3) the reacting is carried out under a pressure of 0.4-1.0 MPa.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 shows the hydrogen spectrum of trans 1,1,1,4,4,4-hexafluoro-2-butene prepared in Example 1 of the present invention.

[0033] FIG. 2 shows the carbon spectrum of trans-1,1,1,4,4,4,4-hexafluoro-2-butene prepared in Example 1 of the present invention.

[0034] FIG. 3 shows the fluorine spectrum of trans-1,1,1,4,4,4,4-hexafluoro-2-butene prepared in Example 1 of the present invention.

DETAILED DESCRIPTION OF THE EXAMPLES

[0035] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments in the present invention, all other embodiments obtained by ordinary skilled in the art without creative labor fall within the protection scope of the present invention.

[0036] In the embodiments and comparison examples, unless otherwise specified, the experimental methods used are conventional methods. The materials, reagents, etc. used can be obtained from commercial sources.

Example 1: Preparation method of trans 1,1,1,4,4,4-hexafluoro-2-butene

(1) Preparation of Carrier

[0037] Pseudo-boehmite and magnesium oxide were mixed in a weight ratio of 45:55, and dissolved in dilute nitric acid. Template agent polyethylene glycol 10000 was added, and a resulting mixture was dried at 100 C., and then calcinated in a muffle furnace at 500 C. for 8 hours, to obtain a catalyst carrier;

(2) Preparation of Catalyst

[0038] The catalyst carrier was immersed in a mixed solution of 5 g/1000 mL ruthenium nitrate and 5 g/1000 mL nickel nitrate, with a solid-liquid ratio of 1:1. A resulting product was dried at 100 C., and then calcinated at a constant temperature of 500 C. in a muffle furnace for 6 hours, to obtain a finished product of 0.5% catalyst, denoted as 0.5Ru/0.5Ni/Al.sub.xMg.sub.yO.sub.z;

(3) Effect Evaluation of the Catalyst

[0039] The evaluation was conducted in a continuous fixed bed reactor. 10 ml of the catalyst was loaded, hydrogen was used as a carrier gas and 2-ethoxy-1,1,4,4,4-hexafluoro-2-butene was a reactant. The reactant is fed by a liquid micro pump. The molar ratio of 2-ethoxy-1,1,4,4,4-hexafluoro-2-butene to hydrogen was 1:2, the space velocity was controlled at 2.5 h.sup.1, the reaction pressure was 1.0 MPa, and the reaction temperature was 225 C. After 6 hours of reaction, sample of the gas phase composition in the reactor was analyzed by gas chromatography. The conversion rate was 97% and the selectivity was 99%.

[0040] The nuclear magnetic resonance data of the reaction product are shown in FIGS. 1-3.

Examples 2-4

[0041] Examples 2-4 were conducted based on Example 1, except that the reaction temperatures were different.

[0042] The specific parameters, conversion rate, and selectivity results are shown in Table 1.

TABLE-US-00001 TABLE 1 Reaction Conversion Selectivity Examples temperature/ C. rate (%) (%) 2 150 80 88 3 180 93 97 4 250 97 63

Examples 5-7

[0043] Examples 5-7 were conducted based on Example 1, except that the reaction pressures were different.

[0044] The specific parameters, conversion rate, and selectivity results are shown in Table 2.

TABLE-US-00002 TABLE 2 Reaction Conversion Selectivity Examples pressure/MPa rate ( %) (%) 5 0.2 79 83 6 0.4 84 95 7 2.0 95 81

Examples 8-10

[0045] Examples 8-10 were conducted based on Example 1, except that the space velocity was changed to evaluate its effect on the reaction.

[0046] The specific parameters, conversion rate, and selectivity results are shown in Table 3.

TABLE-US-00003 TABLE 3 Space Conversion Selectivity Examples velocity/h.sup.1 rate (%) (% ) 8 1.0 75 82 9 1.5 95 95 10 5.0 82 64

Examples 11-13

[0047] Examples 11-13 were conducted based on Example 1, except that the molar ratio of 2-ethoxy-1,1,4,4,4-hexafluoro-2-butene to hydrogen gas was changed to evaluate its effect on the reaction.

[0048] The specific parameters, conversion rate, and selectivity results are shown in Table 4.

TABLE-US-00004 TABLE 4 Selec- the molar ratio of 2-ethoxy-1,1,4,4,4- Conversion tivity Examples hexafluoro-2-butene to hydrogen gas rate ( %) (%) 11 1:1 78 79 12 1:4 95 96 13 1:5 89 88

Examples 14-20

[0049] Examples 14-20 were conducted based on Example 1, except that the catalyst composition and the mass content of the group VIII transition metal were changed to evaluate their effects on the reaction.

[0050] The specific parameters, conversion rate, and selectivity results are shown in Table 5.

TABLE-US-00005 TABLE 5 Conversion Selec- Examples Catalyst composition rate (%) tivity (%) 14 0.5Ru/Al.sub.xMg.sub.yO.sub.z 73 75 15 2.0Ru/Al.sub.xMg.sub.yO.sub.z 88 91 16 5.0Ru/Al.sub.xMg.sub.yO.sub.z 92 90 17 5.0Ru/2.5Ni/Al.sub.xMg.sub.yO.sub.z 91 93 18 5.0Ru/5.0Ni/Al.sub.xMg.sub.yO.sub.z 93 97 19 5.0Ru/2.5Co/Al.sub.xMg.sub.yO.sub.z 78 98 20 5.0Ru/5.0Co/Al.sub.xMg.sub.yO.sub.z 89 99

Comparative Example 1

[0051] The present comparative example was conducted based on Example 1, except that the reaction temperature was 100 C.

[0052] The conversion rate was 32% and the selectivity was 78%.

Comparative Example 2

[0053] The present comparative example was conducted based on Example 1, except that the reaction pressure was 2.5 MPa.

[0054] The conversion rate was 80% and the selectivity was 35%.

Comparative Example 3

[0055] The present comparative example was conducted based on Example 1, except that the space velocity was 0.5 h.sup.1.

[0056] The conversion rate was 72% and the selectivity was 54%.

Comparative Example 4-5

[0057] The present comparative example was conducted based on Example 1, except that the molar ratios of 2-ethoxy-1,1,4,4,4-hexafluoro-2-butene to hydrogen gas were different.

[0058] The specific parameters, conversion rate, and selectivity results are shown in Table 6.

TABLE-US-00006 TABLE 6 the molar ratio of 2-ethoxy-1,1,4,4,4- Selec- Comparative hexafluoro-2-butene Conversion tivity examples to hydrogen gas rate (%) (%) 4 1:10 25 47 5 1:0.5 38 26

Comparative Examples 6-8

[0059] The comparative examples 6-8 were conducted based on Example 1, except that the catalyst compositions were different.

[0060] The specific parameters, conversion rate, and selectivity results are shown in Table 7.

TABLE-US-00007 TABLE 7 Comparative Conversion Selec- examples Catalyst composition rate (%) tivity (%) 6 0.5Pd/0.5Cu/AlxMgyOz 15 48 7 0.5Pt/0.5La/AlxMgyOz 39 76 8 0.5Ru/0.5Ni/AlxMgyOz 32 85

Comparative Examples 9-10

[0061] The comparative examples 9-10 were conducted based on Example 1, except that the raw material compositions were different.

[0062] The specific parameters, conversion rate, and selectivity results are shown in Table 8.

TABLE-US-00008 TABLE 8 Comparative Conversion Selec- examples Raw material composition rate (%) tivity (%) 9 CF.sub.3CHCClCF.sub.3 21 33 10 CF.sub.3CHCFCF.sub.3 29 42

[0063] The above embodiments are only illustrative of the principle and technical effect of the present invention, and are not intended to limit the invention. Any skilled in the arts may modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes within the spirit and technical ideas disclosed in the present invention and completed by those with ordinary knowledge in the technical field should still be covered by the claims of the present invention.