Stabilized rhenium-based heterogeneous catalyst and use thereof

Abstract

The present invention relates to a stabilized rhenium-based heterogeneous catalyst, obtainable by a process comprising contacting a rhenium-based heterogeneous catalyst with a stabilizing agent at a temperature in a range from 0-100 C., the stabilizing agent comprising an aliphatic hydrocarbon compound and use thereof.

Claims

1. A process for preparing an olefin hydrocarbon compound, the process comprising: contacting, in the absence of an olefin feed stream, a rhenium-based heterogeneous catalyst with a stabilizing agent comprising an aliphatic hydrocarbon selected from the group consisting of ethane, ethylene, propane, and propylene, to provide a stabilized rhenium-based heterogeneous catalyst, followed by reacting the olefin feed stream in the presence of the stabilized rhenium-based heterogeneous catalyst to obtain the olefin hydrocarbon compound, wherein the olefin feed stream comprises a C4 olefin, a C5 olefin, or a mixture thereof, and wherein the reacting is carried out at a temperature in a range from 0 to 300 C.

2. The process according to claim 1, wherein the contacting is carried out at a temperature from 0 C. to 100 C. to provide the stabilized rhenium-based heterogeneous catalyst.

3. The process according to claim 1, wherein the contacting is carried out at a temperature from 10 C. to 60 C. to provide the stabilized rhenium-based heterogeneous catalyst.

4. The process according to claim 1, wherein the reacting of the olefin feed stream in the presence of the stabilized rhenium-based heterogeneous catalyst is carried out in a fixed bed reactor.

5. The process of claim 1, wherein the olefin feed stream comprises (i) ethylene and a C4 linear olefin, (ii) ethylene and a C5 linear olefin, or (iii) ethylene and both C4 and C5 linear olefins.

6. The process according to claim 3, wherein the contacting is carried out at a temperature from 20 to 40 C.

7. The process of claim 1, wherein the rhenium-based heterogeneous catalyst comprises elemental rhenium or a rhenium compound, wherein rhenium is present in an amount from 0.01% to 20% by weight of the catalyst.

8. The process of claim 1, wherein the rhenium-based heterogeneous catalyst comprises elemental rhenium or a rhenium compound, disposed on a solid support comprising Al.sub.2O.sub.3, Ga.sub.2O.sub.3, SiO.sub.2, GeO.sub.2, TiO.sub.2, ZrO.sub.2, SnO.sub.2, aluminosilicate, activated carbon, hydrotalcite, an anionic clay, or a mixture thereof.

9. The process of claim 8, wherein the solid support comprises Al.sub.2O.sub.3 or SiO.sub.2.

10. The process of claim 8, wherein the rhenium-based heterogeneous catalyst comprises elemental rhenium, rhenium oxide, rhenium hydride, rhenium sulfide, or rhenium carbide.

11. The process of claim 1, wherein the contacting provides the stabilized rhenium-based heterogeneous catalyst with increased conversion stability and/or increased selectivity to the olefin hydrocarbon compound, relative to performing the reacting alone.

12. The process of claim 11, wherein the olefin feed stream comprises oxygenated compounds.

13. The process of claim 1, wherein the olefin hydrocarbon compound is propylene that is obtained from an olefin metathesis reaction, with ethylene, of the C4 olefin and/or the C5 olefin of the olefin feed stream.

14. The process of claim 1, wherein the rhenium-based heterogeneous catalyst has been subjected to regeneration, prior to the contacting.

15. A process for preparing an olefin hydrocarbon compound, the process comprising: contacting, in the absence of an olefin feed stream, a rhenium-based heterogeneous catalyst with a flow of a stabilizing gas comprising an aliphatic hydrocarbon compound selected from the group consisting of ethane, ethylene, propane, and propylene, to provide a stabilized rhenium-based heterogeneous catalyst, followed by reacting the olefin feed stream in the presence of the stabilized rhenium-based heterogeneous catalyst to obtain the olefin hydrocarbon compound, wherein the olefin feed stream comprises at least one olefin selected from the group consisting of C4 to C12 olefins, and wherein the reacting is carried out at a temperature in a range from 0 to 300 C.

16. The process of claim 15, wherein the olefin feed stream comprises (i) a C2 olefin and a C4 olefin or (ii) a C2 olefin and a C5 olefin.

17. The process of claim 15, wherein the olefin feed stream comprises oxygenated compounds.

18. A process for preparing an olefin hydrocarbon compound, the process comprising: contacting a rhenium-based heterogeneous catalyst with a stabilizing agent comprising ethane or propane, to provide a stabilized rhenium-based heterogeneous catalyst, followed by reacting an olefin feed stream in the presence of the stabilized rhenium-based heterogeneous catalyst to obtain the olefin hydrocarbon compound, wherein the olefin feed stream comprises at least one olefin selected from the group consisting of C2 to C12 olefins, and wherein the reacting is carried out at a temperature in a range from 0 to 300 C.

19. The process of claim 18, wherein the contacting provides the stabilized rhenium-based heterogeneous catalyst with increased conversion stability and/or increased selectivity to the olefin hydrocarbon compound, relative to performing the reacting alone.

20. The process of claim 18, wherein the rhenium-based heterogeneous catalyst has been subjected to regeneration, prior to the contacting.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 illustrates the effect of stabilizing agent on 2-butene conversion;

(2) FIG. 2 illustrates the effect of stabilizing agent on propylene selectivity;

(3) FIG. 3 illustrates the effect of stabilizing temperature on 2-butene conversion;

(4) FIG. 4 illustrates the effect of stabilizing temperature on propylene selectivity;

(5) The following examples illustrate embodiments of the present invention without limiting its scope.

Examples

(6) Several catalysts were prepared according to the invention and compared with catalyst prepared according to the prior art. The catalysts were composed as follows:

(7) Catalyst A (comparative) is a non-stabilized rhenium oxide on gamma-alumina support catalyst.

(8) Catalysts B, C, D, and E are rhenium oxide on gamma-alumina support catalysts according to the invention stabilized by flowing a stabilizing gas through a fixed bed of the catalyst at a stabilizing temperature.

(9) Catalysts F, G, and H (comparative) are rhenium oxide on gamma-alumina support catalysts pretreated by flowing a stabilizing gas through a fixed bed of the catalyst at a high temperature.

(10) Catalysts A to H were subjected to metathesis reaction tests. The tests were carried out by flowing 12 g/h of a C4 olefins mixture and 120 sccm of ethylene through a fixed bed of 6 grams of the catalyst sample at a temperature 30 C. and a pressure 20 bar. Details and results of the tests are shown in Table 1

(11) TABLE-US-00001 TABLE 1 Oxygenate Stabilizing Results at time on stream (hour) content in (Pretreatment) 2-butene conversion Propylene selectivity Test feed stream Stabilizing temperature (%) (%) No. Catalyst (ppm) gas ( C.) 2 h 50 h 100 h 2 h 50 h 100 h 1 A 0.50 None None 89.8 70.4 15.0 97.1 88.8 N/A 2 A 0.65 None None 87.4 45.2 N/A 96.4 71.6 N/A 3 B 0.65 Propylene 30 85.3 51.4 32.0 98.1 81.1 71.9 4 C 0.65 Propane 30 91.0 52.6 N/A 97.2 86.2 N/A 5 D 0.65 Ethane 30 89.7 55.5 41.6 97.1 86.4 81.8 6 E 0.65 Ethylene 30 88.7 69.9 56.2 98.4 88.0 81.6 7 F 0.65 Ethylene 120 80.7 53.7.sup.a N/A 95.6 86.7.sup.a N/A 8 G 0.65 Ethylene 150 12.8 68.4 9 H 0.65 Ethylene 300 7.0 0 Note: (1) N/A means data not available (2) X.sup.a are data measured at time on stream 29 hours

(12) It can be observed from Tests No. 1 and 2 that content of oxygenate substance in the feed stream obviously effect deactivation of the catalyst. In Test No. 3, 4, 5, and 6, the result shows that the use of that stabilized rhenium-based heterogeneous catalyst according to the present invention significantly reduces the effect of the oxygenate substance.

(13) Also, in Tests No. 3, 4, 5, and 6, it can be seen that various hydrocarbon compounds can be utilized as a stabilizing agent in the present invention.

(14) In Tests No. 7, 8, and 9, it can be seen that a higher temperature does not results in a stabilized catalyst in terms of the invention. On the contrary, it significantly has adverse effect on performance of the catalyst.

(15) Comparative results of using catalysts stabilized by different stabilizing agents and non-stabilized catalyst (marked as conventional pretreat) in metathesis reaction of ethylene and mixed C4 streams to produce propylene are illustrated in FIG. 1 and FIG. 2.

(16) Comparative results of using catalysts stabilized by a stabilizing agent at different temperatures and non-stabilized catalysts (marked as convention pretreat) in metathesis reaction of ethylene and mixed C4 streams to produce propylene are illustrated in FIG. 3 and FIG. 4.

(17) The features disclosed in the foregoing description, in the claims and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realizing the invention in diverse forms.

BEST MODE FOR CARRYING OUT THE INVENTION

(18) The best mode of practicing the invention is as described in the above Detailed Description of Invention.