Catalyst system for olefin metathesis

Abstract

The present invention relates to a catalyst system for olefin metathesis, the catalyst system comprising: a) a first system zone substantially comprising a layered double hydroxide; and b) a second system zone comprising a metathesis catalyst.

Claims

1. An olefin metathesis process comprising contacting a feed stream comprising an olefin, with a catalyst system comprising: a. a first system zone comprising a first system zone layered double hydroxide (LDH); and b. a second system zone comprising a metathesis catalyst, wherein said first system zone LDH comprises a first LDH metal and a different, second LDH metal, said first LDH metal selected from the group consisting of Li, Ca, Mg, Mn, Fe, Co, Ni, Cu, and Zn and said second LDH metal selected from the group consisting of Al, Ga, In, Mn, Fe, Co, Cr, Ni, V, Ti, Zr, Y; wherein the metathesis catalyst comprises a transition metal selected from the group consisting of Cr, Mo, W, Mn, Tc, and Re, said transition metal being supported on an inorganic support; wherein the first system zone and the second system zone have different compositions; and wherein the contacting of the feed stream with the catalyst system is performed with temperatures in the first system zone and the second system zone from 200 C. to 450 C.

2. The process of claim 1, wherein the first system zone is placed upstream with respect to the second system zone.

3. The process of claim 1, wherein the metathesis catalyst comprises 0.1 to 60 parts by weight of a zeolite.

4. The process of claim 3, wherein the metathesis catalyst comprises 1 to 20 parts by weight of the zeolite.

5. The process of claim 1, wherein the metathesis catalyst comprises 0.1 to 80 parts by weight of a second system zone layered double hydroxide.

6. The process of claim 5, wherein the metathesis catalyst comprises 1 to 30 parts by weight of the second system zone layered double hydroxide.

7. The process of claim 1, wherein the metathesis catalyst comprises a binder.

8. The process of claim 1, wherein a weight ratio of the first system zone layered double hydroxide to the metathesis catalyst is from 0.5:1 to 10:1 by weight.

9. The process of claim 8, wherein the weight ratio of the first system zone layered double hydroxide to the metathesis catalyst is from 2:1 to 4:1 by weight.

10. The process of claim 1, wherein the transition metal of the metathesis catalyst is selected from the group consisting of molybdenum, tungsten, rhenium, and mixtures thereof.

11. The process of claim 1, wherein the inorganic support of the metathesis catalyst is selected from the group consisting of silica, alumina, titania, zirconia, and mixtures thereof.

12. The process of claim 3, wherein the zeolite of the metathesis catalyst is selected from the group consisting of ZSM-5, X-zeolite, Y-zeolite, -zeolite, MCM-22, ferrierite, and mixtures thereof.

13. The process of claim 1, wherein the first LDH metal is selected from the group consisting of Li, Ca, Mg, Fe, Co, Ni, Cu, Zn, and mixtures thereof.

14. The process of claim 13, wherein the second LDH metal is selected from the group consisting of Al, Ga, In, Fe, Co, Cr, Ni, V, Ti, Zr, Y, and mixtures thereof.

15. The process of claim 1, wherein the first system zone layered double hydroxide comprises an anion selected from the group consisting of chloride, bromide, carbonate, bicarbonate, hydrogen phosphate, dihydrogen phosphate, nitrite, borate, nitrate, sulfate, phosphate, hydroxide, fluoride, iodide, and mixtures thereof.

16. The process of claim 1, wherein the feed stream comprises ethylene, propylene, or a linear olefin selected from the group consisting of a C4 linear olefin, a C5 linear olefin, a C6 linear olefin, and mixtures thereof.

17. The process of claim 1, wherein the metathesis catalyst comprises a second system zone layered double hydroxide comprising a second system zone first LDH metal selected from the group consisting of Li, Ca, Mg, Mn, Fe, Co, Ni, Cu, Zn, and mixtures thereof.

18. The process of claim 17, wherein the second system zone layered double hydroxide further comprises a second system zone second LDH metal selected from the group consisting of Al, Ga, In, Mn, Fe, Co, Cr, Ni, V, Ti, Zr, Y, and mixtures thereof.

19. The process of claim 1, wherein the metathesis catalyst comprises a second system zone layered double hydroxide comprising an anion selected from the group consisting of chloride, bromide, carbonate, bicarbonate, hydrogen phosphate, dihydrogen phosphate, nitrite, borate, nitrate, sulfate, phosphate, hydroxide, fluoride, iodide, and mixtures thereof.

20. The process of claim 1, wherein the first system zone does not comprise any further catalytic active species, or comprises said further catalytic active species only in an amount that does not significantly influence catalytic properties of the first system zone.

Description

(1) The invention works for the olefin metathesis reaction, most preferably in the olefin metathesis reaction between ethene and butene to produce propene. Additional features and advantages of the present invention will become apparent in the following detailed description on the basis of examples with reference to the drawings, wherein

(2) FIG. 1 illustrates two embodiments of the inventive catalyst system.

(3) FIG. 2 illustrates propene yield results of various catalyst systems measured along reaction time on stream.

EXAMPLE 1 (COMPARATIVE)

(4) Metathesis catalyst powder is obtained by depositing 9 wt % of WO.sub.3 on a support containing 95 wt % of silica and 5 wt % of Y-zeolite and then physically mixing with MgAlCO.sub.3 layered double hydroxide in the ratio of 10:1 by weight. The catalyst powder was packed in a tube reactor, then a feed stream comprising ethene and 2-butene was supplied to react over the catalyst at 350 C. and 22 bar gauge to produce propene. Propene yield achieved was 61 wt %.

EXAMPLE 2

(5) A metathesis catalyst was obtained by physically mixing 9 wt % WO.sub.3 on a support containing 95 wt % of silica and 5 wt % of Y-zeolite with MgAlCO.sub.3 layered double hydroxide in the ratio of 10:1 by weight. 2.2 g of white clay (binder) and 110 mL of demineralized water was added to 110 g of the metathesis catalyst and the powder and water are immediately threshed to activate the binder and get homogeneous wet pre-extruded catalyst. Next, the wet catalyst is fed into an extruder. Then, the catalyst extrudate, getting from the extruder, is dried at 150 C. for 3-4 hr in an oven. The obtained catalyst was subjected to a reaction test where ethene and 2-butene are reacted to form propene over the catalyst at 350 C. and 22 bar gauge with 3 options of the upstream system zone as follow for comparison.

(6) TABLE-US-00001 TABLE 1 Upstream system zone Propene yield (wt %) None 35 MgO 70 MgAlCO3 LDH 99

(7) It can be seen from the above results that placing a bed of a layered double hydroxide catalyst upstream to a metathesis catalyst can relieve, and even improve, catalyst efficiency drop occurred after catalyst shaping.

EXAMPLE 3

(8) Various catalyst systems were prepared as displayed in Table 2.

(9) TABLE-US-00002 TABLE 2 Catalyst System Fisrt system zone No. (upstream) Second system zone (downstream) 1 10 wt % WO.sub.3/90 wt % Si.sub.2O.sub.3 2 MgO 10 wt % WO.sub.3/90 wt % Si.sub.2O.sub.3 3 MgAlCO.sub.3 LDH 10 wt % WO.sub.3/90 wt % Si.sub.2O.sub.3 4 MgO 10 wt % WO.sub.3/78 wt % Si.sub.2O.sub.3/3 wt % Y-zeolite/9 wt % MgAlCO3 LDH 5 MgAlCO.sub.3 LDH 10 wt % WO.sub.3/78 wt % Si.sub.2O.sub.3/3 wt % Y-zeolite/9 wt % MgAlCO3 LDH 6 MgAlNO.sub.3 LDH 10 wt % WO.sub.3/78 wt % Si.sub.2O.sub.3/3 wt % Y-zeolite/9 wt % MgAlCO3 LDH 7 ZnAlCO.sub.3 LDH 10 wt % WO.sub.3/78 wt % Si.sub.2O.sub.3/3 wt % Y-zeolite/9 wt % MgAlCO3 LDH

(10) These catalyst systems were subjected to reaction test by packing 1.5 grams of the second system zone (downstream) material as a bottom layer and 3 grams of the first system zone (upstream) material as a top layer in a tube reactor. A feed stream containing approximately 25 wt % ethene, 15 wt % n-butenes, 5 wt % i-butene, and balancing C4 paraffins were fed into the reactor to contact with the catalyst system at 350 C., 20 bar gauge, and WHSV 3.5 h.sup.1. Test results are displayed in Table 3.

(11) TABLE-US-00003 TABLE 3 Catalyst Total Butenes Selectivity System Conversion to Propene No. (wt %) (wt %) 1 5 50 2 30 92 3 55 96 4 31 90 5 54 95 6 58 97 7 54 96

(12) Propene yields measured along reaction time on stream are shown in FIG. 2.

(13) It can be seen that activity, selectivity, and reaction stability were significantly improved when a bed of layered double hydroxide is placed upstream to the metathesis catalyst.

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