Catalyst support, process for its preparation and use

Abstract

An open-pore catalyst support comprising a material that comprises a natural sheet silicate and ZrO.sub.2. In order to provide a catalyst support, by means of which alkenyl acetate catalysts can be prepared which are characterized by a high level of alkenyl acetate activity over a relatively long period, the catalyst support comprises a material that comprises a natural sheet silicate and ZrO.sub.2 in the tetragonal modification.

Claims

1. An open-pore catalyst support, comprising a material that comprises a natural sheet silicate and ZrO.sub.2 in the tetragonal crystalline phase, wherein the catalyst support in boiling acetic add releases less than 0.06 wt.-%, Zr calculated as ZrO.sub.2, relative to the weight of the ZrO.sub.2 contained in the catalyst support, and wherein the ZrO.sub.2 is contained in the catalyst support in a proportion of 1 wt.-% to 30 wt.-%.

2. An open-pore catalyst support material comprising a natural sheet silicate and ZrO.sub.2, wherein the catalyst support in boiling acetic add releases less than 0.06 wt.-% Zr calculated as ZrO.sub.2, relative to the weight of the ZrO.sub.2 contained in the catalyst support, and wherein the ZrO.sub.2 is contained in the catalyst support in a proportion of 1 wt.-% to 30 wt.-%.

3. The catalyst support of claim 1, wherein at least 50 wt.-% of the ZrO.sub.2 contained in the catalyst support is present in the tetragonal crystalline phase.

4. The catalyst support of claim 1, wherein the ZrO.sub.2 is present in particulate form.

5. The catalyst support of claim 1, wherein the ZrO.sub.2 is contained evenly distributed in the material.

6. The catalyst support of claim 4, wherein the ZrO.sub.2 particles are evenly distributed over the cross-section of the support and wherein the support is essentially free of a percolation network of ZrO.sub.2 particles.

7. The catalyst support of claim 1, wherein the natural sheet silicate is an acid-activated sheet silicate.

8. The catalyst support of claim 1, wherein the catalyst support has an acidity of 1 val/g to 150 val/g.

9. The catalyst support of claim 1, wherein the catalyst support has an average pore diameter of 7 nm to 30 nm.

10. The catalyst support of claim 1, wherein the catalyst support has a specific surface area of less than/equal to 180 m.sup.2/g.

11. The catalyst support of claim 1, wherein the catalyst support has a specific surface area of 180 m.sup.2/g to 60 m.sup.2/g.

12. The catalyst support of claim 1, wherein the catalyst support has a hardness greater than/equal to 30 N.

13. The catalyst support of claim 1, wherein the proportion of natural sheet silicate in the catalyst support is at least 50 wt.-%, relative to the weight of the catalyst support.

14. The catalyst support of claim 1, wherein the catalyst support has an integral pore volume of 0.25 ml/g to 0.7 ml/g.

15. The catalyst support of claim 1, wherein at least 80% of the integral pore volume of the catalyst support is formed from mesopores and macropores.

16. The catalyst support of claim 1, wherein the catalyst support has a bulk density of more than 0.45 g/ml.

17. The catalyst support of claim 1, wherein the natural sheet silicate contained in the catalyst support has an SiO.sub.2 content of at least 65 wt.-%.

18. The catalyst support of claim 1, wherein the natural sheet silicate contained in the support contains less than 5 wt.-% Al.sub.2O.sub.3.

19. The catalyst support of claim 1, wherein the catalyst support is formed as a shaped body.

20. The catalyst support of claim 1, wherein the catalyst support has a maximum size of 1 mm to 25 mm.

21. The catalyst support of claim 19 formed as a sphere.

22. The catalyst support of claim 21, wherein the sphere has a diameter of 2 mm to 10 mm.

23. The catalyst support of claim 1, wherein the catalyst support is doped with at least one oxide of a metal selected from the group consisting of Hf, Ti, Nb, Ta, W, Mg, Re, Y and Fe.

24. The catalyst support of claim 23, wherein the proportion of doping oxide in the catalyst support is 1 wt.-% to 20 wt.-%.

25. The catalyst support material of claim 2, wherein the ZrO.sub.2 is present in particulate form.

26. The catalyst support material of claim 2, wherein the ZrO.sub.2 is contained evenly distributed in the material.

27. The catalyst support material of claim 25, wherein the ZrO.sub.2 particles are evenly distributed over the cross-section of the support material and wherein the support material is essentially free of a percolation network of ZrO.sub.2 particles.

28. The catalyst support material of claim 2, wherein the natural sheet silicate is an acid-activated sheet silicate.

29. The catalyst support of claim 2, wherein the catalyst support has an acidity of 1 val/g to 150 val/g.

30. The catalyst support material of claim 2, wherein the catalyst support material has an average pore diameter of 7 nm to 30 nm.

31. The catalyst support material of claim 2, wherein the catalyst support material has a specific surface area of less than/equal to 180 m.sup.2/g.

32. The catalyst support material of claim 2, wherein the catalyst support material has a specific surface area of 180 m.sup.2/g to 60 m.sup.2/g.

33. The catalyst support material of claim 2, wherein the catalyst support material has a hardness greater than/equal to 30 N.

34. The catalyst support material of claim 2, wherein the proportion of natural sheet silicate in the catalyst support material is at least 50 wt.-%, relative to the weight of the catalyst support.

35. The catalyst support material of claim 2, wherein the catalyst support material has an integral pore volume of 0.25 ml/g to 0.7 ml/g.

36. The catalyst support material of claim 2, wherein at least 80% of the integral pore volume of the catalyst support material is formed from mesopores and macropores.

37. The catalyst support material of claim 2, wherein the catalyst support material has a bulk density of more than 0.45 g/ml.

38. The catalyst support material of claim 2, wherein the natural sheet silicate contained in the catalyst support has an SiO.sub.2 content of at least 65 wt.-%.

39. The catalyst support material of claim 2, wherein the natural sheet silicate contained in the support contains less than 5 wt.-% Al.sub.2O.sub.3.

40. The catalyst support material of claim 2, wherein the catalyst support material is formed as a shaped body.

41. The catalyst support material of claim 2, wherein the catalyst support material has a maximum size of 1 mm to 25 mm.

42. The catalyst support of claim 41 formed as a sphere.

43. The catalyst support of claim 42, wherein the sphere has a diameter of 2 mm to 10 mm.

44. The catalyst support material of claim 2, wherein the catalyst support material is doped with at least one oxide of a metal selected from the group consisting of Hf, Ti, Nb, Ta, W, Mg, Re, Y and Fe.

45. The catalyst support of claim 44, wherein the proportion of doping oxide in the catalyst support material is 1 wt.-% to 20 wt.-%.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The examples below serve, in conjunction with the drawing, to describe the invention. There are shown in:

(2) FIG. 1: Section of an EDX photograph of a first catalyst support according to aspects of the invention according to example 1;

(3) FIG. 2: XRD spectrum of the first catalyst support according to aspects of the invention;

(4) FIG. 3: Section of an EDX photograph of a second catalyst support according to aspects of the invention according to example 1a;

(5) FIG. 4: XRD spectrum of a catalyst support of the state of the art according to example 4;

(6) FIG. 5: Section of an EDX photograph of the catalyst support according to example 4.

EXAMPLE 1

(7) 500.0 g of an acid-treated dried powdery bentonite (acid-activated bentonite) with the main constituent montmorillonite as sheet silicate was mixed with a quantity of Zr(OH).sub.4 customary in the trade corresponding to 61.875 g of ZrO.sub.2, with a d.sub.10 value of approx. 1 m, a d.sub.50 value of approx. 5 m and with a d.sub.90 value of 7 m, and also with 10 g of a customary organic binder/pore-forming agent.

(8) Water was added to the resultant mixture and it was processed by means of a mixer into a dough from which spherical shaped bodies (d=5 mm) were prepared under pressure by means of a tablet press. For hardening, the spheres were dried and calcined at a temperature of 650 C. over a period of 5 h. After the calcining, the shaped bodies were treated with 20% hydrochloric acid over a period of 30 h, washed with plenty of water and calcined at a temperature of 600 C. over a period of 5 h. The thus-obtained shaped bodies have the characteristics listed in Table 1:

(9) TABLE-US-00001 TABLE 1 Geometric form Sphere Diameter 5 mm Moisture content 0.5 wt.-% Compressive strength 60 N Bulk density 607 g/l Water absorbency 58% Specific surface area (BET) 133 m.sup.2/g SiO.sub.2 content 81.6 wt.-% ZrO.sub.2 content 12.8 wt.-% ZrO.sub.2 yield 98% Proportion of tetragonal ZrO.sub.2 >90 wt.-% (determined according to XRD diffractogram) Al.sub.2O.sub.3 content 2.5 wt.-% Loss on ignition 1000 C. 1.5 wt.-% Acidity 62 val Integral pore volume 0.377 ml/g Zr release 0.001 wt.-% Average pore diameter (according to BJH) (4V/A) 10.5 nm Proportion of the integral pore volume <1% accounted for by micropores Proportion of the integral pore volume 14.3% accounted for by pores with a diameter of 2.0 nm to 6 nm Proportion of the integral pore volume 70.2% accounted for by pores with a diameter of 6.0 nm to 50 nm Proportion of the integral pore volume 84.5% accounted for by pores with a diameter of 2.0 nm to 50 nm Average particle size d.sub.50 of the ZrO.sub.2 20 m (determined from EDX mapping)

(10) A catalyst support according to example 1 was halved and the cut surface of one half measured by means of energy-dispersive X-ray spectroscopy (EDX). FIG. 1 shows a section of the EDX photograph. The homogeneous statistical distribution of the ZrO.sub.2 particles (dark spots) in the support matrix is clearly visible.

(11) A catalyst support according to example 1 was ground to a powder and measured by X-ray diffractometry. The resulting XRD spectrum is shown in FIG. 2. Only signals from tetragonal ZrO.sub.2 can be identified in the XRD spectrum. No monoclinic or cubic ZrO.sub.2 can be identified in the spectrum.

EXAMPLE 1a

(12) Catalyst supports were prepared analogously to example 1, differing only in that a quantity of Zr(OH).sub.4 customary in the trade corresponding to 132 g of ZrO.sub.2 was used. The thus-obtained shaped bodies have the characteristics listed in Table 1a:

(13) TABLE-US-00002 TABLE 1a Geometric form Sphere Diameter 5 mm Moisture content 0.4 wt.-% Compressive strength 33 N Bulk density 580 g/l Water absorbency 67.1% Specific surface area (BET) 132 m.sup.2/g SiO.sub.2 content 69.5 wt.-% ZrO.sub.2 content 24.5 wt.-% ZrO.sub.2 yield 99% Proportion of tetragonal ZrO.sub.2 >90 wt.-% (determined according to XRD diffractogram) Al.sub.2O.sub.3 content 1.8 wt.-% Loss on ignition 1000 C. 1.6 wt.-% Acidity 23 val Integral pore volume 0.4 ml/g Zr release 0.001 wt.-% Average pore diameter (according to BJH) (4V/A) 11 nm Proportion of the integral pore volume <1% accounted for by micropores Proportion of the integral pore volume 13.6% accounted for by pores with a diameter of 2.0 nm to 6 nm Proportion of the integral pore volume 71.7% accounted for by pores with a diameter of 6.0 nm to 50 nm Proportion of the integral pore volume 85.3% accounted for by pores with a diameter of 2.0 nm to 50 nm Average particle size d.sub.50 of the ZrO.sub.2 20 m (determined from EDX mapping)

(14) A catalyst support according to example 1a was halved and the cut surface of one half measured by means of EDX. FIG. 3 shows a section of the EDX photograph. The homogeneous statistical distribution of the ZrO.sub.2 particles (light spots) in the support matrix is clearly visible.

EXAMPLE 1b

(15) Catalyst supports were prepared analogously to example 1, differing only in that the catalyst supports were treated with hydrochloric acid for a period of only 8 h. The thus-obtained shaped bodies have the selected characteristics listed in Table 1b:

(16) TABLE-US-00003 TABLE 1b ZrO.sub.2 content 12.6 wt.-% Proportion of tetragonal ZrO.sub.2 >90 wt.-% (determined according to XRD diffractogram) Zr release 0.002 wt.-% Average pore diameter (according to BJH) 7.7 nm (4V/A) ZrO.sub.2 yield 98.5%

EXAMPLE 2

(17) Catalyst supports were prepared analogously to example 1, differing in that the first calcining was carried out after the shaping at only 550 C. The thus-obtained shaped bodies have the selected characteristics listed in Table 2:

(18) TABLE-US-00004 TABLE 2 ZrO.sub.2 content 9.6 wt.-% Zr release 0.001 wt.-% Average pore diameter (according 11 nm to BJH) (4V/A) ZrO.sub.2 yield 76% The thus-obtained support has a ZrO.sub.2 yield of only 76% and a ZrO.sub.2 content of 9.6 wt.-%.

EXAMPLE 3

Comparison Example

(19) A catalyst support commercially available from Sd-Chemie AG, Munich, Germany with the trade name KA-160 for example has the characteristics listed in Table 3:

(20) TABLE-US-00005 TABLE 3 Geometric form Sphere Diameter 5 mm Water absorbency 66.4% Specific surface area (BET) 161 m.sup.2/g SiO.sub.2 content 91.8 wt.-% Al.sub.2O.sub.3 content 3.6 wt.-% Average pore diameter (according to BJH) (4V/A) 10.3 nm Integral pore volume 0.436 ml/g Proportion of the integral pore volume accounted 11.0% for by pores with a diameter of 2.0 nm to 6 nm Proportion of the integral pore volume accounted 71.6% for by pores with a diameter of 6.0 nm to 50 nm Proportion of the integral pore volume accounted 82.7% for by pores with a diameter of 2.0 nm to 50 nm

EXAMPLE 4

Comparison Example

(21) (cf. U.S. Pat. No. 5,808,136) 74.6 g of an aqueous solution of zirconyl acetate (ZrO(OAc).sub.2), which had a Zr content of 15.5 wt.-% was diluted with approx. 8.5 ml of water. 100 g of the catalyst support KA-160 from Sd-Chemie AG according to example 3 was impregnated with the above solution. The impregnated support was dried and calcined at 500 C. The resulting catalyst support had a zirconium content of approx. 10 wt.-% (calculated as corresponding to 13.53 wt.-% ZrO.sub.2). Further characteristics of the support are listed in Table 4:

(22) TABLE-US-00006 TABLE 4 Geometric form Sphere Diameter 5 mm Water absorbency 49.1% Specific surface area (BET) 134 m.sup.2/g Zr content* 10 wt.-% SiO.sub.2 content 80.9 wt.-% Zr release* 0.129 wt.-% Al.sub.2O.sub.3 content 3 wt.-% Average pore diameter (according to BJH) (4V/A) 9.1 nm Integral pore volume 0.332 ml/g Proportion of the integral pore volume accounted 20.0% for by pores with a diameter of 2.0 nm to 6 nm Proportion of the integral pore volume accounted 65.1% for by pores with a diameter of 6.0 nm to 50 nm Proportion of the integral pore volume accounted 85.2% for by pores with a diameter of 2.0 nm to 50 nm *For calculation purposes, the ZrO.sub.2 content of 13.53 wt.-% ascertained by calculation from the Zr content is used

(23) FIG. 4 shows the XRD spectrum of a catalyst support prepared according to example 4. It is clear from the spectrum that the Zr in the support is not present in an X-ray diffraction active oxide form.

(24) A catalyst support according to example 4 was halved and the cut surface of one half measured by means of EDX. FIG. 5 shows a section of the EDX photograph. No discrete zirconium-containing particles are visible.

EXAMPLE 5

Comparison Example

(25) Catalyst supports were prepared analogously to example 1, differing only in that 57.8 g of a 20% zirconyl nitrate solution diluted with 19.7 ml of water was used. Characteristics of the thus-obtained support are listed in Table 5:

(26) TABLE-US-00007 TABLE 5 Zr content* 2.6 wt.-% Zr release* 0.06 wt.-% *For calculation purposes, the ZrO.sub.2 content of 3.51 wt.-% ascertained by calculation from the Zr content is used. Note: On drying, enriched zirconyl nitrate separates from the surface resulting in a high loss of zirconium.

Comparative Overview

(27) In Table 6 the average pore diameter, the integral pore volume and proportions of particular pore sizes in the integral pore volume of examples 3, 4, 1 and 1a are compared.

(28) TABLE-US-00008 TABLE 6 Example 3 4 1 1a Average pore 10.3 nm 9.1 nm 10.5 nm 11.0 nm diameter (according to BJH) (4V/A) Integral pore 0.436 0.332 0.377 0.40 volume ml/g ml/g ml/g ml/g Proportion of the 11.0% 20.0% 14.3% 13.6% integral pore volume accounted for by pores with a diameter of 2.0 nm to 6 nm Proportion of the 71.6% 65.1% 70.2% 71.7% integral pore volume accounted for by pores with a diameter of 6.0 nm to 50 nm Proportion of the 82.7% 85.2% 84.5% 85.3% integral pore volume accounted for by pores with a diameter of 2.0 nm to 50 nm

(29) The subsequent impregnation of the commercial KA-160 support of example 3 with Zr according to example 4 leads to a significant reduction in the integral pore volume and to a narrowing of pores. The proportion of pores of 2 nm to 6 nm increases significantly, at the expense of the mesopores greater than 6 nm. However, compared with the catalyst support of example 3, the catalyst support prepared according to aspects of the invention and according to the process according to aspects of the invention according to examples 1 and 1a, despite doping with 12.8 wt.-% or 24.5 wt.-% ZrO.sub.2, has an overall higher or at least comparable proportion of mesopores in the case of an increased average pore diameter.

(30) The Zr releases of examples 1, 1a, 1b, 2, 4 and 5 are compared in Table 7.

(31) TABLE-US-00009 TABLE 7 Example 1 1a 1b 2 4 5 Zr release 0.001 0.001 0.002 0.001 0.129 0.060 [wt.-%] The catalyst supports of examples 1, 1a and 1b and 2 have a clearly reduced Zr release compared with examples 4 and 5.